1st international conference on electrolysis

International Conference on Electrolysis

2017I C E

1st International Conference on Electrolysis

12 – 15 June 2017

Book of abstracts

Venue: Axelborg, Copenhagen, Denmarkhttp://ice2017.net

Sponsor:

1stInternationalConferenceonElectrolysisCopenhagen,12-15June2017

1

Idea and Scope for the ICE series

Electrolyzer events are rare and real conference series perhaps non-existing. Electrolyzers are equivalent to fuel cells, but while conferences devoted to fuel cells are plentiful, electrolyzer conferences are certainly not. Scientific and technical exchange of knowledge regarding electrolyzers are typically taking place in sub-sessions of fuel cell conferences or overarching hydrogen conferences like the WHEC. You may have joined one-at-a-time workshops or thematic meetings on electrolysis, but full-blown international conference series where the growing community can gather, network and share the latest findings in a regular manner remain to be seen.

Research in all the aspects of electrolysis for energy conversion is growing, and the awareness that the conversion from electrical energy to storable and portable matter - fuels - is an inevitable part of the green transition from a fossil based energy infrastructure to asustainable one. Fuel cells are expected to play a vital role in this transition too, but theycompete with proven and well-established technologies, while electrolyzers bridge a gab forwhich no other alternative is obvious. On this background it is even more striking that wehave not yet managed to put up a designated conference series on electrolysis for energyconversion.

The aim of this initiative is to start a conference series devoted to electrolysis for energy conversion. Let us make a forum in which electrolysis is the main theme and not a sub-topic among many others. We prepared the setting for the fist event in a nice venue, but only the participants can ensure the success – now and for the years to come.

Welcome at ICE2017 in Copenhagen

Jens Oluf Jensen Chair of ICE2017


2

Invited Speakers

EverettB.Anderson–ProtonOnSite(US)

AntoninoArico–CNR(IT)

PeterBlennow–HaldorTopsoeA/S(DK)

OliverBorm–Sunfire(DE)

TianshanChen–PurificationEquipmentResearchInstituteofCSIC(CN)

NickvanDijk–ITM(UK)

StevenHoldcroft–SimonFraserUniversity(CA)

JohnIrvine–UniversityofSt.Andrews(UK)

NikolaosLymperopoulos–FCHJointUndertaking(B)

PierreMillet–UniversitéParisSud(FR)

MogensB.Mogensen–DTUEnergy(DK)

BryanPivovar–NREL(US)

ThomasJ.Schmidt–PSI(CH)

BjørnSimonsen–NELHydrogen(NO)

CarlStoots–IdahoNationalLaboratory(US)

JanVaes–Hydrogenics(B)

ManfredWaidhas–Siemens(DE)

HuiXu–GinerInc.(US)


3

International Scientific Committee

DmitriBessarabov-HySAInfrastructureatNorth-WestUniversity(ZA)

MarceloCarmo-ForschungszentrumJülich(DE)

EunAeCho-KoreaAdvancedInstituteofScienceandTechnology(KR)

JohnT.S.Irvine-UniversityofStAndrews(UK)

JürgenMergel-ForschungszentrumJülich(DE)

PierreMillet-UniversitéParisSud(FR)

BryanPivovar-NationalRenewableEnergyLaboratory(US)

YangShao-Horn-MassachusettsInstituteofTechnology(US)

TomSmolinka-FraunhoferISE(DE)

CarlStoots-IdahoNationalLaboratory(US)

MagnusThomassen-SINTEF(NO)


4

Local Organising Committee

JensOlufJensen-DTUEnergy

MogensBjergMogensen-DTUEnergy

AnneHauch-DTUEnergy

LailaGrahlMadsen-EWIIFuelCells

SørenKnudsenKær-AalborgUniversity

LarsNilausenCleemann-DTUEnergy

David Aili-DTUEnergy

LeneChristensen-DTUEnergy

JensQAdolphsen-DTUEnergy

ChristodoulosChatzichristodoulou-DTUEnergy

MingChen-DTUEnergy

KatrineElsøe-DTUEnergy

FilippoFenini-DTUEnergy

LiHan -DTUEnergy

MikkelRykærKraglund-DTUEnergy

SebastianMolin-DTUEnergy

AlekseyNikiforov-DTUEnergy

CarstenBrorsonPrag-DTUEnergy

SaherAlShakhshir-AalborgUniversity

ShahidAli-AalborgUniversity

SamuelSimonAraya-AalborgUniversity

SteffenFrensch-AalborgUniversity

SaeedSadeghiLafmejani-AalborgUniversity

AndersOlesen-AalborgUniversity


5

ProgrammeOverview

Mon12 Tue13 Wed14 Thu1508:00 Arrival+reg.08:30 Arrival+reg. Arrival+reg. Arrival+reg.09:00 Opening09:20 Talks Talks Talks Talks09:40 Other PEMFC SOEC AEC10:0010:2010:40 Coffee Coffee Coffee Coffee11:0011:20 Talks Talks Talks Talks11:40 PEMEC AEC PEMEC SOEC12:0012:2012:4013:00 Lunch Lunch Lunchbuffet Lunch13:20 andPosterII13:4014:00 Talks Talks EWII Talks14:20 AEC SOEC presentation PEMEC14:40 14:3015:0015:20 Coffee Coffee Coffee15:40 Harbourtour16:00 Talks Talks 15.30-16.30 Talks16:20 SOEC PEMEC AEC16:40 Closing17:0017:20 Coffee Free17:4018:00 Welcome Talks18:20 reception Other Drink18:40 PosterI19:0019:2019:40 Sci. Dinner20:00 Committee Axelborg20:20 Meeting20:4021:0021:2021:4022:0022:2022:4023:00


6

Programme Monday12/6

08:30 Registration,Coffee

09:00-10:40 Session1.Special Chair:LailaGrahlMadsen No.

09:00 Welcome,openingremarksJensOlufJensen

DTUEnergyDenmark

09:20 ApplicationofPotentiallyInexpensiveCeramicsinElectrolysisCells

MogensB.Mogensen(INVITED)DTUEnergyDenmark

1

09:40 OverviewofFCHJUsupporttoElectrolysisforenergyapplications

NikolaosLymperopoulos(INVITED)FCH-JU,EnergyPillar

Belgium2

10:00EfficientseawaterelectrolyzerbasedonNickelIronlayereddoublehydroxideas

selectiveOxygenevolutionreactioncatalyst

SörenDrespTechnischeUniversitätBerlin

Germany3

10:20

Corrosion-resistantmaterialsforuseinunconventionalmoltencarbonate

electrolysisenvironments:evaluationofAl-diffusioncoatingsforstainlesssteel

protectioninaternaryLiNaKcarbonatemeltat500°CunderCO2gas

StefanoFranginiENEAItaly

4

10:40 Coffeebreak

11:00-12:40 Session2.PEMEC Chair:MarceloCarmo No.

11:00 AdvancingPEMElectrolysisforCurrentandFutureHydrogenMarkets

EverettB.Anderson(INVITED)ProtonOnSite

USA5

11:20 KeyPerformanceIndicatorsforMW-scalePEMwaterelectrolyzers

PierreMillet(INVITED)UniversiteParisSud

France6

11:40 BusinessOpportunitiesforMWelectrolysisandrelatedRequirements

ManfredWaidhas(INVITED)SiemensAGGermany

7

12:00StackdesignforaMegawattscalePEMelectrolyser,andoverviewoftheFCH-JU

projectMEGASTACK

MagnusThomassenSINTEFNorway

8

12:20Techno-EconomicModelingofRenewableEnergyHydrogenSupplySystemsbasedon

WaterElectrolysis

ØysteinUllebergInstituteforEnergyTechnology

Norway9

12:40 Lunch


7

Monday12/6(Continued)

13:40-15:20 Session3.AEC Chair:KarelBouzek No.

13:40 TheOxygenEvolutionReaction:TheEnigmainWaterElectrolysis

ThomasJ.Schmidt(INVITED)PaulScherrerInsitute

Switzerland10

14:00

OxygenEvolutionReactiononPerovskites:ACombinedExperimentalandTheoreticalStudyofTheirStructural,Electronic,and

ElectrochemicalProperties

XiChengPaulScherrerInstitut

Switzerland11

14:20ElectrocatalysisofOxygen-Evolutionon

Well-DefinedMass-SelectedNiFenanoparticles

ClaudieRoyTechnicalUniversityofDenmark

Denmark12

14:40 Raney-Nielectrodesforthealkalineelectrolysisofwater

ChristianMüllerFraunhoferIFAM

Germany13

15:00 RaneyNickelalloyelectrodesforalkalinewaterelectrolysis

Syed-AsifAnsarGermanAerospaceCenter

Germany14

15:20 Coffeebreak

15:40-17:20 Session4.SOEC Chair:JohnIrvine No.

15:40 RolesforHighTemperatureElectrolysisintheRapidlyChangingUSEnergyMarket

CarlStoots(INVITED)IdahoNationalLaboratory

USA15

16:00 SolidOxideElectrolysisforGridBalancing:RecentAchievementsandFutureChallenges

MingChenDTUEnergyDenmark

16

16:20 Operationandperformanceoftubularprotonceramicelectrolysers

EinarVøllestadUniversityofOslo

Norwawy17

16:40 FabricationandCharacterizationofMetal-supportedSolidOxideElectrolysisCells

FengHanGermanAerospaceCenter(DLR)

Germany18

17:00SolidOxideElectrolyzerCellsoxygen

electrodebasedoninfiltratednanocompositemesoporousmaterials

ElbaHernándezCataloniaInstituteforEnergyResearch-

IRECSpain

19

17:20-19:40 PostersessionI Withwelcomereception


8

Tuesday13/608:30

Registration,Coffee

09:00-10:40 Session5.PEMEC Chair:MagnusThomassen No.

09:00ThedevelopmentandimplementationofIr

basednanowiresasoxygenevolutionelectrocatalysts

BryanPivovar(INVITED)NRELUSA

20

09:20 TheoxygenevolutionatIrxRu1-xO2producedbyhydrolysissynthesis

SveinSundeNTNUNorway

21

09:40

StudyofthePhysicalMorphologyandElectrochemicalCharacteristicsofOxygenEvolutionReaction(OER)IridiumBasedElectrocatalystSynthesizedwithaPolyol

MethodforPEMWaterElectrolysis

BrantAPeppleyQueen'sUniversity

Canada22

10:00 AnodecatalystsforPEMelectrolyzers:Synthesis,ActivityandDegradationAspectswithExSituandInSituCharacterization

LiWangGermanAerospaceCenter(DLR)

Germany23

10:20 Onthedesignandoptimizationofabimetallic(Co,Mn)-basedcatalystforhydrogenevolutioninacidicmedium

AliShahraeiTUDarmstadtGermany

24

10:40Coffeebreak

11:00-12:40 Session6.AEC Chair:ThomasJ.Schmidt No.

11:00 Hydrogenreachingfossilparityaroundtheworld

BjørnSimonsen(INVITED)NelHydrogen

Norway25

11:20 PERIC’sdevelopmentonAELandSPEtechnology

TianshanChen(INVITED)PurificationEquipmentResearch

InstituteofCSICChina

26

11:40 AlkalineWaterElectrolyzersWithBaseMetalCatalystsShowing1A/cm2At1.75V

RichardIMaselDioxideMaterials

USA27

12:00

AuniqueapproachforhighintensityalkalinewaterelectrolysisusingamembranelessDivergent-Electrode-Flow-Through(DEFT

TM)electrolyser

MalcolmGillespieHydroxHoldingsLtd.

SouthAfrica28

12:20 HightemperaturealkalineelectrolysisChristodoulosChatzichristodoulou

DTUEnergyDenmark

29

12:40 Lunch


9

Tuesday13/6(Continued)

13:40-15:20 Session7.SOEC Chair:CarlStoots No.

13:40 TailoringelectrodeinterfacesforconversionJohnT.S.Irvine(INVITED)UniversityofStAndrews

UK30

14:00

DegradationBehaviorof(La,Sr)(Fe,Co)O3SolidOxideCellOxygenElectrodesDuring

ReversibleElectrolysisandFuelCellOperation

ScottBarnettNorthwesternUniversity

USA31

14:20Eliminatingdegradationandrepairingdamageinsolidoxidecellandstackfuel

electrodes

TheisSkafteDTUEnergyDenmark

32

14:40 Post-testanalysisofasolidoxideelectrolysiscelloperatedfor23000h

QingxiFuEIFER

Germany33

15:00Regeneratingtheperformanceofsolidoxide

electrolyzersbyperiodictreatmentstoextendlifetime

ChristopherGravesDTUEnergyDenmark

34

15:20 Coffeebreak

15:40-17:20 Session8.PEMEC Chair:BryanPivovar No.

15:40

MegawattscaledualstackPEMelectrolysisdevelopmentforenhancingrenewable

energyintegrationbyprovidinggridservicesduringhydrogengeneration

JanVaes(INVITED)HydrogenicsBelgium

35

16:00IncreasingPEMwaterelectrolysisenergeticefficiencybyasurfacemodificationofTigas

diffusionlayer

KarelBouzekUniversityofChemistryandTechnology

PragueCzechRepublic

36

16:20 MaterialsandcoatingsforPEMwaterelectrolysers

AlejandroOyarceSINTEFNorway

37

16:40 Flowfielddesignforhigh-pressurePEMelectrolysiscells

AndersOlesenAalborgUniversity

Denmark38

17:00Protectivecoatingsforlow-costbipolarplatesandcurrentcollectorsofprotonexchangemembraneelectrolyzers

PhilippLettenmeierGermanAerospaceCenter

Germany39

17:20 Coffeebreak


10

Tuesday13/6(Continued)

17:40-19:20 Session9.Special Chair:SørenKnudsenKær No.

17:40 EUHarmornisedTestProtocolsforElectrolysisApplications

GeorgiosTsotridisJointResearchCentre

Netherlands40

18:00 CatalyticandPhotochemically-AssistedElectroreductionofCarbonDioxide

PawelKuleszaUniversityofWarsaw

Poland41

18:20 Impactofthedesignonperformancelossinphoto-drivenwaterelectrolysers

FredyNandjouEPFL/LRESESwitzerland

42

18:40 SO2depolarizedelectrolyser-EnhancedH2productionwithSiCfoamflowlayer

AnnukkaSantasalo-AarnioAaltoUniversity

Finland43

19:00 SputteredPt-containingelectrocatalystsforSO2(aq)electrolysis

AnzelFalchNorth-WestUniversity

SouthAfrica44

19:20 ScientificCommitteemeeting


11

Wednesday14/6


09:00-10:40 Session10.SOEC Chair:AnneHauch No.

09:00SteamElectrolysisastheCoreTechnology

forSectorCouplingintheEnergyTransition

OliverBorm(INVITED)SunfireGmbHGermany

45

09:20 ElectrochemicalTailoringofSyngasSeverinFoit

ForschungszentrumJülichGermany

46

09:40 Systemdesignandoperationofasolidoxideelectrolyzer

LigangWangEPFL

Switzerland47

10:00 Solidoxideelectrolyzessystemdevelopment

RichardSchauperlAVL

Austria48

10:20ElectrochemicalCharacterizationofa10

layerSolidOxideElectrolysisStackoperatedunderpressurizedconditions

MarcRiedelGermanAerospaceCenter

Germany49

10:40 Coffeebreak

11:00-12:40 Session11.PEMEC Chair:PierreMillet No.

11:00 TheDevelopmentofAcceleratedStressTestsforPEMElectrolysers

NicholasvanDijk(INVITED)ITMPower

UK50

11:20 BenchmarkingCatalystActivityandDurabilityforWaterElectrolysis

HuiXu(INVITED)GinerInc.

USA51

11:40Operationoflow-tempelectrolyzersatveryhighcurrentdensities:apipedream

oranopportunity?

KrzysztofLewinski3MUSA

52

12:00Membranesforrecombinationand

electro-oxidationofpermeatedhydrogeninPEMelectrolysis

DmitriBessarabovHySAatNorth-WestUniversity

SouthAfrica53

12:20 Physicalfactorsaffectinggas-leakagefromPEMWE

KoheiItoKyushuUniversity

Japan54

12:40-15:00 PosterSessionII WithlunchandpresentationbyEWII


12

Wednesday14/6(Continued)

15:00 DepartureforCopenhagenHarbourtour

15:30-16:30 CopenhagenHarbourtour

18:00 Drink

19:00-23:00 ConferenceDinner


13

Thursday15/6


09:00-10:40 Session12.AEC Chair:ChristodoulosChatzichristodoulou No.

09:00 Polyaromatic,SolidPolymerElectrolytesforAcidicandAlkalineElectrolyzers

StevenHoldcroft(INVITED)SimonFraserUniversity

Canada55

09:20Recentdevelopmentsinalkalinepressure

electrolysiswithanion-conductivemembrane(AEM)

UlrichFischerBrandenburgUniversityofTechnology

Germany56

09:40Anionselectivemembranesbasedlaboratory-scalealkalinewater

electrolysisstack

JaromírHnátUniversityofChemistryandTechnology

PragueCzechRepublic

57

10:00 HighTemperatureMembranelessAlkalineElectrolysis

JeremyHartvigsenMissouriS&T

USA58

10:20 AlkalinemembraneelectrolysiswithPEM-levelelectrochemicalperformance

MikkelRykærKraglundDTUEnergyDenmark

59

10:40 Coffeebreak

11:00-12:40 Session13.SOEC Chair:ScottBarnett No.

11:00 COfromCO2–on-sitecarbonmonoxidegeneration

PeterBlennow(INVITED)HaldorTopsoeA/S

Denmark60

11:20

Thermodynamicconstraintsinoperatingasolidoxideelectrolysisstackondry

carbondioxidegatheredfromtheMarsatmosphere

JosephHartvigsenCeramatec,Inc.

USA61

11:40DevelopmentandflightqualificationofasolidoxideCO2electrolysisstackforthe

Mars2020MOXIEproject

JessicaElwellCeramatec,Inc

USA62

12:00

SyntheticmethaneproductionfromCO2methanation:processintegrationwith

SOECelectrolyserandreactionkineticsonhydrotalcite-derivedcatalystand

AndreaLanziniPolitecnicodiTorino

Italy63

12:20Performanceanddurabilityoffour6-cell

solidoxideelectrolyserstacksforhydrogenandsyngasproduction

MikkoKotisaariVTT

Finland64

12:40 Lunch


14

Thursday15/6(Continued)

13:40-15:20 Session14.PEMEC Chair:DmitriBessarabov No.

13:40

EffectofcatalystloadingonperformanceanddurabilityofaPEMwaterelectrolysis

cellbasedonanAquivion®perfluorosulfonicacid(PFSA)membrane

AntoninoS.Arico'(INVITED)CNR-ITAE

Italy65

14:00AgingofPEMWEcatalystcoated

membranesduringdynamicoperation:Electrochemicalandmicroscopicstudy

GeorgiosPapakonstantinouMaxPlanckInstituteforDynamicsof

ComplexTechnicalSystemsGermany

66

14:20 DurabilityofPEMECMEAsLailaGrahl-Madsen

EWIIFuelCellsDenmark

67

14:40Towardsselectivetestprotocolsfor

acceleratedinsitudegradationofPEMelectrolysiscellcomponents

ThomasLickertFraunhoferISE

Germany68

15:00Mechanicalcharacterisationand

durabilityofsinteredbodiesforPEMelectrolysis

ElenaBorgardtResearchCenterJuelich

Germany69

15:20 Coffeebreak

15:40-17:00 Session15.AEC Chair:StevenHoldcroft No.

15:40Complexofcobaltandmolybdenum

carbidenanoparticlesforefficientoxygenevolutionreactioninalkalineelectrolytes

EunaeChoKAIST

RepublicofKorea70

16:00Gold-MetalOxideCore-Shell

NanoparticlesAsElectrocatalystsforWaterOxidation

MariaEscudero-EscribanoUniversityofCopenhagen

Denmark71

16:20 Modifiedcarbonnanomaterialsashighlyactiveelectrocatalystsforwater-splitting

MohammadTavakkoliAaltoUniversity

Finland72

16:40-17:00 ClosingJensOlufJensen

DTUEnergyDenmark


15

Monday12/6-POSTERSESSION

PostersessionI Withwelcomereception No.

Influenceofgeometryandkineticofhydrogenandoxygenevolutiononthe

currentdensitydistributionandelectrodepotentialsinbipolarelectrolyzers

AlejandroColli(EPFL)

Switzerland101

Ion-solvatingpolymerelectrolytesforalkalinewaterelectrolysis

DavidAiliDTUEnergyDenmark

102

Nickel/Tungsten-CarbideComposite

CatalystsforOxygenEvolutioninAlkalineWaterElectrolysis

DonghoonSongKAIST

RepublicofKorea103

Bubblecharacterizationinanelectrolysiscellusingaflowvisualizationsystem

ErnestoAmoresCentroNacionaldelHidrógeno

Spain104

AFacileSynthesisofNano-sizedIrO2andRuO2CatalystsfortheOxygenEvolution

ReactioninAlkalineMedium

GüntherG.A.SchererTUMCREATESingapore

Switzerland105

DFTstudiesofdopedCobaltandNickelOxyhydroxideCatalystsforOxygen

Evolution

HeineHansenDTUEnergyDenmark

106

A3-DmicroporousCo-Fe-Pcatalystforoxygenandhydrogenevolutionreactions

inalkalinewaterelectrolysis

HyowonKimKAIST

RepublicofKorea107

Processintensificationofalkalinewaterelectrolysisbyusing3-Delectrodes

QuentinDeRadiguèsUniversitécatholiquedeLouvain

Belgique108

DonQuichote:DemonstrationofHowtoProduceHydrogenUsingWindEnergy

AhmedAlyFASTItaly

109

MaterialsandcoatingsforPEMwaterelectrolysers

AlejandroOyarceSINTEFNorway

110

FromPolyelectrolytestoRobust,HighlyProtonConductingHydrocarbon

MembranesforPEMFuelCellandPEMElectrolysisApplications

AndreasMünchingerMax-Planck-InstituteforSolidState

ResearchGermany

111

InvestigationonporoustransportlayersforPEMelectrolysis

ArneFallischFraunhoferISE

Germany112


16

Monday12/6-POSTERSESSION(Continued)

Acceleratedstresstestsforefficientdegradationstudiesoniridium-basedmixedmetaloxidecatalystsforPEM-

electrolysis

CamilloSpoeriTechnischeUniversitätBerlin

Germany113

Directmembranedeposition–asimpleandcosteffectivefabricationmethodforpolymerelectrolytemembraneelectrolysis

cells

CarolinKloseUniversityofFreiburg

Germany114

Experimentalanalysisoflocaleffectsina50cmPEMwaterelectrolysiscell

ChristophImmerzLeibnizUniversität

Germany115

ModellingandSimulationActivitiesonPEMWaterElectrolysis

DeepjyotiBorahForschungszentrumJuelich

Germany116

Investigationofadvancedcomponentsinahighpressuresingle-cellelectrolyserfor

thedevelopmentofaHP-PEM-ELYstackaspartofaRegenerativeFuelCellSystem

DimitriosNiakolasFORTH/ICEHT

Greece117

PermeationandRecombinationofHydrogenunderPEMelectrolysis

conditions

DmitriBessarabovHySAatNorth-WestUniversity

SouthAfrica118

DesignofReferenceElectrodeforPolymerElectrolyteMembraneElectrolyzer

ElyseJohnston-HaynesQueen'sUniversity

Canada119

Electrospun-TiO2Supportingmaterialsfor

OxygenEvolutionReactioninAcidicconditions

Eom-JiKimKAIST

RepublicofKorea120

PEM-ElectrodedryingFabianScheepers

ForschungszentrumJuelichGermany

121

Polymerfunctionalizedcarbonnanotubes

ashighlyactivebifunctionalelectrocatalysisforfullwatersplitting

FatemehDavodiAaltouniversity

Finland122

Spinel-structuredmaterialsascatalystsupport/currentcollectormaterialsfor

PEMelectrolysiscells

FilippoFeniniDTUEnergyDenmark

123

Hydrogenproductionfromshort-chain

alcoholsusingpolymericprotonconductors

FoteiniSapountziSyngaschemBVNetherlands

124


17


SinglecrystalstudiestoevaluatethestructuresensitivityoftheOxygen

EvolutionReaction(OER)underacidicconditions

FrancescoBizzottoUniversityofBern

Switzerland125

ImpactofDynamicLoadfromRenewable

EnergySourcesonPEMElectrolyzerLifetime

FransvanBerkelECN

TheNetherlands126

ResearchandDemonstrationofSolidPolymerElectrolysisTechnologyinChina

XiaofengXieTsinghuaUniversity

China127

ProgressoftheEuropeanProjectEfficientCo-ElectrolyserforEfficientRenewable

EnergyStorage-ECo

AnkeHagenDTUEnergyDenmark

128

ComparativedegradationstudyofaNi-YSZ

supportedSolidOxideFuelCellunderelectrolysisandco-electrolysisoperations

AzizNechacheGermanAerospaceCenter

Germany129

PerformanceanddegradationofaSOECstackwithdifferentairelectrodes

CarolinFreyForschungszentrumJülich

Germany130

SynergiesbetweenSolidOxideElectrolyserCellsandCatalyticMethanisation

ChristianDannesboeAarhusUniversity

Denmark131

Techno-economicstudyofaReversibleSolidOxideCell(SOC)systemforindustrialhydrogenproductionandgridsupport

applications

DomenicoFerreroPolitecnicodiTorino

Italy132

SolidoxideelectrolysisatForschungszentrumJülich

DominikSchäferForschungszentrumJülich

Germany133

3DprintedelectrolytesforSolidOxideElectrolyserdeviceswithcomplex

hierarchicalgeometries

ElbaHernándezCataloniaInst.forEnergyResearch(IREC)

Spain134

DevelopmentofSOECstacksatDTUEnergy

HenrikLundFrandsenDTUEnergyDenmark

135

MeasurementofeffectivediffusionforNi/YSZmaterialusedforSOFC/SOECwithaWicke-KallenbachsetupandassessmentofconcentrationprofilesduringCO2-andco-

electrolysis

JakobDuhnDTUChemicalEngineering

Danmark136


18


OrbitalPhysicsofActivePerovskitesforOxygenCatalysis

JoseGraciaSynCatDIFFERNetherlands

137

Determiningthefractureenergyforoxygenelectrodeandcontactlayer

interfacesinSOECsstacks

LiHanDTUEnergyDenmark

138

Hightemperatureelectrolyserwithprotonconductingceramictubularcells

NuriaBausáITQ(UPV-CSIC)

Spain139

SpecificelectricalconductivityinsolidandmoltenCsH2PO4andCs2H2P2O7

–apotentiallynewelectrolyteforwaterelectrolysisat~225-400°C

AlekseyNikiforovDTUEnergyDenmark

140

OxygenEvolutionReactionPerformanceofPrBaCo2O5+δandBa0.5Sr0.5Co0.8Fe0.2O2+δin

CarbonatedElectrolyteforWaterElectrolysis

BaejungKimPaulScherrerInstitut

Switzerland141

ThecatalysisoftheelectrolyticproductionofH2O2

IfanStephensDTUPhysicsDenmark

142

Bioreactorwithinsituwaterelectrolysisforproteinproduction

LauriNygrenLappeenrantaUniversityofTechnology

LUTSchoolofEnergySystemsFinland

143


19

Wednesday14/6-POSTERSESSION

PostersessionII WithlunchandpresentationbyEWII

No.

DevelopmentofoxygenevolutionelectrocatalystsandelectrodesforHighTemperatureandPressureAlkaline

ElectrolysisCells(HTP-AEC)

JensQ.AdolphsenDTUEnergyDenmark

201

Hydrogenproductionfromphotovoltaicvia“zerogap”alkalineelectrolysis

JirinaPolakovaUJVRez,a.s.CzechRepublic

202

Mathematicalmodelandexperimentalvalidationofa15-kWalkalineelectrolyzer

MónicaSánchezCentroNacionaldelHidrógeno

Spain203

ActivityofplasmavapourdepositedPtxNiyAlzasanodeelectrocatalystfor

(membraneless)alkalinewaterelectrolysis

RoelofJacobusKriekNorth-WestUniversity

SouthAfrica204

Small-scalesystemsforalkalinewaterelectrolysis

UlrichVogtEmpa

Switzerland205

Newseparatorconceptsforaradical

improvementofthegasqualityinalkalinewaterelectrolysis(AWE)

WimDoyenVITO

Belgium206

ControlandenergyefficiencyofalkalineandPEMwaterelectrolyzersinrenewable

energysystems

JoonasKoponenLappeenrantaUniversityofTechnology

Finland207

Theeffectoflinefrequencyandforcedcommutationonthelossesofthe

electrolyzerstackandthepowersupplyunit

VesaRuuskanenLappeenrantaUniversityofTechnology

Finland208

HydrogenproductionasapartofP-to-Xsystem

AnttiKosonenLappeenrantaUniversityofTechnology

Finland209

DetectionandmodellingofhydrogencrossoverinPEMelectrolysersusingEIS

JulioCésarGarcía-NavarroGermanAerospaceCenter

Germany210

DemonstrationofImpedanceSpectroscopyasaMethodtoEvaluate

LossesofPolymerElectrolyteMembraneElectrolysisCellsduringWaterElectrolysis

KatrineElsøeDTUEnergyDenmark

211

EngineeringofhightemperaturePEMWEKoheiIto

KyushuUniversityJapan

212


20

Wednesday14/6-POSTERSESSION(Continued)

TheHyBalanceProjectwilldemonstratehowhydrogencanbeusedasmeanto

storeenergywhichinturnwillbeusedforIndustryandfuel-cellvehicles

LouisSentisAirLiquideAdvancedBusiness

France213

AdvancesinPEMElectrolyzerComponentsMadeleineOdgaard

EWIIFuelCellsDenmark

214

DeterminationofthebipolarplateagingunderPEMelectrolysisoperation

ManuelLangemannForschungszentrumJülich

Germany215

H2FUTURE,Hydrogenfromelectrolysisforlowcarbonsteelmaking

MarcelWeedaECN

Netherlands216

Ironsulfidesaslow-costbioinspired

cathodecatalystsforprotonexchangemembraneelectrolyzers

MarionGiraudUniversiteParisDiderot

France217

TungstenCarbideSupportMaterialsfortheHydrogenEvolutionReactionProducedbytheSelf-PropagatingHigh-Temperature

SynthesisMethod

MortenGildsigPoulsenUniversityofSouthernDenmark

Denmark218

CurrentdensityimpactonhydrogenpermeationduringPEMwaterelectrolysis

PatrickTrinkeLeibnizUniversität

Germany219

HighlyActiveIridiumNanoparticlesforAnodesofProtonExchangeMembrane

(PEM)Electrolyzers

PhilippLettenmeierGermanAerospacecenter

Germany220

DegradationmechanismsofPEM

electrolyzerMEAsoperatingathighcurrentdensities

PhilippLettenmeierGermanAerospacecenter

Germany221

Experimentalanalysisofgas-liquidflowinPEMwaterelectrolysermini-channels

usingapermeablewall

SaeedSadeghiLafmejaniAalborgUniversity

Denmark222

Experimentalstudyontheinfluenceofclampingpressureonprotonexchangemembranewaterelectrolyzer(PEMWE)

cell’scharacteristics

SaherAlShakhshirAalborgUniversity

Denmark223

FabricationofporousCo-Pfoamby

electrodepositionforanefficienthydrogenandoxygenevolutionreactions

SekwonOhKAIST

RepublicofKorea224

APEMwaterelectrolyserbasedon

metalliciridiumelectrocatalyst,Pt/CandanAquivionmembrane

StefaniaSiracusanoCNR-ITAE

Italy225


21


ConceptualDegradationModelforaPEMWaterElectrolyzer

SteffenFrenschAalborgUniversity

Denmark226

AnalysisofPorousTransportLayersforProtonExchangeWaterElectrolysis

TobiasSchulerPaulScherrerInstitut

Switzerland227

Plasma-chemicaltechnologiesforPEMelectrolyzerscatalystsandprotective

coatings

VladimirFateevNRC"Kurchatovinstitute"

Russia228

ModifiedNiO/GDCcermetsaspossiblecathodeelectrocatalystsforH2O

electrolysis&H2O/CO2co-electrolysisprocessesinSOECs

DimitriosNiakolasFORTH/ICEHT

Greece229

InoperandoRamanspectroscopyforinvestigationofsolidoxideelectrolysis

cells

MarieLundTraulsenDTUEnergyDenmark

230

OxygenevolutionreactionkineticsonLSMelectrodedopedbyPt

MartinPaidarUniversityofChemistryandTechnology

PragueCzechRepublic

231

Experimentalloopofhightemperature

electrolysisincouplingofhightemperatureprocess

MartinTkáčTechnologicalExperimentalLoops

CzechRepublic232

Distributionofrelaxationtimes–toolfortheanalysisofimpedancespectra

PiotrJasinskiGdanskUniversityofTechnology

Poland233

In-situupgradingofbio-oilusingsolidoxideelectrolysisprocess

S.ElangoElangovanCeramatec,Inc.UnitedStates

234

InfiltratedSolidOxideCellOxygen

Electrodes:DegradationDuringReversibleCurrent-SwitchingOperation

ScottBarnettNorthwesternUniversity

USA235

Protectivecoatingsforinterconnectsforsolidoxidecellstacks

SebastianMolinDTUenergyDenmark

236

PowertoGas/Liquid-biomassgasificationandSOECcombinedsystem

ShahidAliAalborgUniversity

Denmark237

LSCFandLSCinfiltratedLSCFelectrodeforhightemperaturesteamelectrolysis

VaibhavVibhuForschungszentrumJülich

Germany238


22


UnderstandingandTailoringActivityandStabilityofPerovskiteandManganese

OxidesfortheOxygenEvolutionReaction

VladimirTripkovicDTUEnergyDenmark

239

INSIDE–In-situDiagnosticsinWaterElectrolysers

IndroBiswasGermanAerospaceCentre

Germany240

Innovativephotoelectrochemicalcellsbasedonpolymericmembraneelectrolytesandsuitableporous

photoanodes

MichailTsampasDIFFER

Netherlands241

ElectrolysersbasedonCsH2PO4toworkat

highpressuresandmoderatetemperatures

NuriaBausá/LauraNavarreteITQ(UPV-CSIC)

Spain242


23

AbstractNo.1(INVITED)

ApplicationofPotentiallyInexpensiveCeramicsinElectrolysisCells

MogensB.Mogensena,KatrineElsøea,FilippoFeninia,KentK.Hansena,PeterHoltappelsa,JohanHjelma,ChristodoulosChatzichristodouloua

aTechnicalUniversityorofDenmark,DepartmentofEnergyConversionandStorage,Roskilde,[email protected]

Summary. The aims of this presentation are: 1) to give an overview of inexpensive ceramics already used for cellcomponentslikeelectrodes,porousmembranesanddiaphragmsforliquidelectrolyteimmobilization,andsupportsforelectrocatalystsandcells;2)tooutlinestrategiesforsearchofstableandefficientelectro-ceramicsforelectrolysis.

Abstract.ItseemsgenerallyagreedthatthewholeworldwillneedelectrolysisofwaterandCO2forstoringrenewableenergyinarelativelynearfuture.Alsoaneedforelectrolysistypeofcellsforproductionofchemicalsandfuelsareappearing,andR&Dactivitieshavebeenstarted.However,thereisamainproblemfortheseapplications,namelythecosts.

Commercialelectrolysiscellsexist. Cellssuchasalkalineelectrolysiscellsforproductionofhighpurityhydrogenforindustrialpurposes,andcellsforchlor-alkaliandchlorateprocesseshavebeencommerciallyavailableduringmorethana century [1,2]. Even though these types of cells are technically excellent for hydrogen production, they are tooexpensivefortheenergysector.Alotmaybelearnedfromtheseoldtechnologies,butthecostsmustbedecreasedsignificantly.

Somemain typesofelectrolysis cells,AEC (alkalineelectrolysis cell) [3,4,5],PEMEC (polymerelectrolytemembraneelectrolysiscell)[3,6],MCEC(moltencarbonateelectrolysiscell)[7]andSOEC(solidoxideelectrolysiscell)[5,8,9]willbe reviewed with respect to state of the art materials and performance, followed by considerations on possiblestrategiestodecreasethecostsbyimprovingcellperformanceanddurabilityofcellsbasedonnon-preciouselementswithemphasisonceramicmaterials.

Finally, possible interrelationships between structure, stability, conductivity and catalytic activity of oxides will beoutlined.

[1]R.K.B.Karlsson,A.Cornell,Chem.Rev.,116,2982(2016).[2]F.F.Rivera,C.P.deLeón,J.L.Nava,F.C.Walsh,Electrochim.Acta,163,338(2015).[3]A.Ursúa,L.M.Gandía,P.Sanchis,Proc.IEEE,100,410(2012).[4]C.Chatzichristodoulou,F.Allebrod,M.B.Mogensen,J.Electrochem.Soc.163,F3036(2016).[5]S.D.Ebbesen,S.H.Jensen,A.Hauch,M.B.Mogensen,Chem.Rev.,114,10697(2014).[6]M.Carmo,D.L.Fritz,J.Mergel,D.Stolten,Internat.J.HydrogenEnergy,38,4901(2013).[7]L.Hu,G.Lindbergh,C.Lagergren,J.Phys.Chem.C,120,13427(2016).[8]C.Graves,S.D.Ebbesen,S.H.Jensen,S.B.Simonsen,M.B.Mogensen,NatureMaterials14,239(2015).[9]C.Graves,L.Martinez,B.R.Sudireddy,ECSTransactions72(7),18(2016).


24


OverviewofFCHJUsupporttoElectrolysisforenergyapplications

NikolaosLymperopoulos

ProjectOfficer,FuelCellsandHydrogenJointUndertakingNikolaos.Lymperopoulos@fch.europa.eu

Summary.AnoverviewofthesupportprovidedbytheFCHJUtothedevelopmentanddemonstrationofelectrolysersispresentedalongwiththesuccessofthesectorinreachingrespectiveKeyPerformanceIndicators.

Abstract. The Fuel Cells and Hydrogen Joint Undertaking is a Public Private partnership between the EuropeanCommissionandEuropeanIndustryandResearchers,itsaimbeingtohelphydrogenenergytechnologiesreachmarketreadinessby2020.Outof the728MEuroofsupportprovidedbytheFCHJUsince its launch,93MEuro (13%)wereprovidedto36projectsonHydrogenProductiontopicsandoutofthose69MEuro(9.5%)to23projectsonelectrolysers.Electrolysersarethustheworkhorseforrenewablehydrogenproductionand indeedhavethe lowestCO2footprint(27gCO2/kWhH2)andhighestTRL(7-8)comparedtootherrouteslikebiogasreforming(203gCO2/kWhH2,TRL8),biomassgasification (162gCO2/kWhH2, TRL 7), concentrated solar for the thermal dissociation of water (TRL 5) or photo-electrochemicaldevices(TRL3).

PEMelectrolysershavereceivedhalfofFCHJUelectrolysissupport(35.6MEuro)withtwolargedemonstrationprojects(Hybalance and H2Future) accounting for 20MEuro. Solid Oxide electrolysers have received 20MEuro for researchprojectsasthistechnologyisatlowerTRLlevels.Alkalineelectrolysersbeingthemostmaturetechnologyhavereceived9MEuroforResearchplusonelargedemonstration(Demo4Grid).

ThistypeofsupporthasledtoAlkalineandPEMelectrolysersmeetingsomeoftheKeyPerformanceIndicatorssetbytheFCHJUascanbeseeninthetablebelowwheretheinternationalStateoftheArtisalsoshown.

Besidessupport to technologydevelopmentanddemonstration, theFCHJU is supporting theEuropeanelectrolysissectorthroughstudieslikethe“CommercialisationofEnergyStorageinEurope”studythatidentifiedalongterm(2050)potentialof170GWofelectrolysersinGermanyifH2costsof2Euro/kgcanbereached.Thefindingsofastudyon“Earlybusinesscases forHydrogen inEnergyStorage”willbeavailable inSpring2017andwillbe included in thepresentpublication.

PEME AECAPEX,M€/(t/d) < 3.7 1.7-3.5

@1MW/500kg/d

Energyconsumption,kWh/kg < 55 65Efficiencydegradation,%/y < 2 1.1Minload,%ofnominalcapa. - < 5 0Maxload,%ofnominalcapa. - > 150 100Hotstart,seconds < 10 10Coldstart,seconds < 120 300

FCHJUprojectresults2015 MAWPtarget2017

non-European

SoA


25

AbstractNo.3

EfficientseawaterelectrolyzerbasedonNickelIronlayereddoublehydroxideasselectiveOxygenevolutionreactioncatalyst

SörenDrespa,FabioDionigia,PeterStrasseraaTechnicalUniversityBerlin

[email protected]

Summary.AnefficientalkalinemembranebasedseawaterelectrolyzerwasinvestigatedbyusingNiFe-layereddoublehydroxideasselectiveseawaterOxygenevolutionreactioncatalyst

Abstract.Intimesofenergyrevolution,renewableenergysavingplaysanever-increasingrole.Commonlyusedwaterelectrolysis for hydrogen production requires precleaned or easily available freshwater sources. The direct use ofseawatercouldpromotesustainableenergytechnologyinareasofscarcefreshwaterbuteasilyaccessibleseawater.Torealizeaseawaterelectrolyzer,aselectiveOxygenevolutionreaction(OER)catalystthatsimultaneouslysuppressestheChlorineevolutionreaction(ClER)isrequired.

Basedonaseawaterelectrolysisdesigncriterion1,highlycrystallineNickelIronlayereddoublehydroxides(NiFe-LDH)was identifiedandpreparedtobetested inamembranebasedelectrolyzerusinganionexchangemembranes.ThecrystallinitywasconfirmedbyusingX-raydiffraction (XRD)andelementalcompositionbyusing inductivelycoupledplasma-opticalemissionspectrometry(ICP-OES).Thecatalystmaterialsweretestedinartificialseawater(0.5MNaCl)anddifferentKOHconcentrations.AcurrentdropwasdeterminedwhenaddingNaCltotheelectrolyte,whileincreasingtheKOHconcentrationcounteractedthelossincurrentdensity.Toexplorethiseffect,theanionexchangemembranes(AEM)werefurtherinvestigatedregardingtheirIonconductivityatdifferentKOHandNaClconcentrationsusingafour-electrode set-up. Long-term stabilities were further tested galvanostatically and as load alternating day/nightmeasurements.Afterreapplyingapotential,astrong“recoveryeffect”wasdiscoveredthatcouldhelpincreaseoverallactivityandefficiency.

Figure1:Simplifiedmodelofmembranebasedalkalineseawaterelectrolyzerandthecorrespondinganodereactions

References

1. Dionigi,F.;Reier,T.;Pawolek,Z.;Gliech,M.;Strasser,P.,ChemSusChem2016,9(9),962-972.


26

AbstractNo.4

Corrosion-resistantmaterialsforuseinunconventionalmoltencarbonateelectrolysisenvironments:evaluationofAl-diffusioncoatingsforstainlesssteel

protectioninaternaryLiNaKcarbonatemeltat500°CunderCO2gas

StefanoFranginia,LucaTurchettia,ClaudioFeliciaandAlessandraBelluccibaENEACRECasaccia,Dept.EnergyTechnologies,ViaAnguillarese301,00123Rome,Italy

bCentroSviluppoMaterialiS.p.A,ViadiCastelRomano100,00128Rome,ItalyCorrespondingauthor:[email protected]

Summary.Anewsteamelectrolysisprocessineutecticmoltencarbonateelectrolytesisunderinvestigation.Adequatecorrosion-resistantmaterialsneedtobeidentifiedforasuccessfulimplementationoftheelectrolysisprocess.CorrosionstabilityofAl-diffusioncoatingsinaternaryLiNaKmoltencarbonatehasbeenstudiedat500°CunderCO2gas.

Abstract.Accordingtoseveralscenario-basedprojections,hightemperaturesteamelectrolysis(HTSE)isexpectedtoplayanimportantroleinthenearfutureeitherforchemicalenergystorageapplicationsorforsustainableproductionofH2byrenewableenergysources.Althoughmostcurrentresearchfocusesontemperatures>750°Candsolidoxideelectrolyzers formaximum conversion efficiency, we have recently started the study of a novel steam electrolysisprocessatintermediatetemperatures,thatisataround500°C,whichisoptimalforuseofheatandelectricityproducedinConcentratingSolarPowerplants.Theproposedsolar-poweredelectrolysisprocessusesaternaryeutecticmoltencarbonateelectrolytewithameltingpointof397°C.AlthoughthesteamissuppliedtothecathodesidemixedwithCO2,onlysteamissubjectedtoelectrolysisreactionsintheoperatingconditions,whereastheroleofCO2istokeepastablemolten carbonate electrolyte composition and to assist the cathode reaction.Due to theunconventional corrosiveenvironment, studies with small-scale electrolytic cells are currently in progress to identify suitable electrode andstructuralmaterials for process optimization, cell design and scale-up. In this context, experience from theMoltenCarbonateFuelCell(MCFC)technologyindicatesthatAl-diffusioncoatingscanofferstableprotectionagainststainlesssteelmoltencarbonatecorrosion,althoughlowertemperaturesandhighercontentoftheCO2corrosivegasarepresentintheelectrolysisprocessascomparedtoMCFC.Therefore,thecorrosionbehaviorofAl-diffusioncoatingsinmoltencarbonateshasbeenrecheckedundermoreappropriateelectrolysisconditions.Forthispurpose,a316Lstainlesssteelsamplewasaluminizedbypackcementationandthenpre-oxidizedinairat750°Cforimprovingitscorrosionresistance.Finally,thealuminizedsamplewasimmersedforhalfofitssizeineutecticLi/Na/Kcarbonatesaltat500°CunderpureCO2gasfora48hperiod.ThecorrosionresistanceoftheAl-diffusioncoatinginthedifferentzonesofthesamplewasevaluatedbySEM/EDXanalysis.ResultsofthecorrosiontestwillbereportedatthetimeoftheConference.


27


AdvancingPEMElectrolysisforCurrentandFutureHydrogenMarkets

EverettB.Anderson,KatherineE.AyersandStephenSzymanski

ProtonOnSite,10TechnologyDrive,Wallingford,CT06043USA

[email protected]

Summary.PEMElectrolysishasbeensatisfyingindustrialapplicationsforhydrogenformorethan20yearsandisnowpoised to leverage that same successful commercial track record for the emerging renewable energy andmobilitymarketsforhydrogen.

Abstract.Hydrogenisanimportantindustrialgas,representinga10millionmetrictons/yearindustryworth$100billion.Currentlyover95%ofthathydrogenismadefromfossilfuels:naturalgasreformingorcoalgasification.Closeto50%of the world’s annual hydrogen production is used for ammonia generation and oil refining, with the hydrogengenerationbeingthehighestenergyandhighestemissionsubcomponentofammoniageneration.Inaddition,2%ofU.S. energy currently goes through hydrogen as an intermediate, a number that will increase substantially whenhydrogen-fuelledvehiclesbecomewidespread.TomeettheClimateActionPlangoalsof80%reductioningreenhousegasemissionsby2050,netzerocarbonpathwaysforhydrogenproductionarethereforecritical.

There are several pathways to generating hydrogen from renewable sources, but one of the most advanced ismembrane-basedwaterelectrolysispoweredbysolar,wind,orhydropower.Whileelectrolysishasbeendemonstratedatmegawattscale,thereisstillsignificantpromiseforfurtherimprovement.Severalcountriesarealreadycommittedtoadvancingthistechnology,andareworkingonthecriticalmaterialsissuesthatdrivecostandefficiency.Longertermtechnologiessuchasphotoelectrochemicalwatersplittingorthermochemicalroutesmayprovidelowercostpathwaysintheend,butneedtobuildfromtechnologiesthathavealreadybeendevelopedatrelevantscale.

The"perfect"technologytoaddresstheenergychallengewillalwaysbe20yearsaway.Asnewconceptsmovefrombasicprinciples tobench-scaleexperiments andbeyond, thepitfallsbecomeclearer. At the same time,dismissingexistingcommercial technologiesbecauseof limitationswhichmightbecomerelevantatmulti-gigawattorterawattscalepreventsus frommaximizingearly impactonsustainability. Commercialprotonexchangemembrane (PEM)-basedelectrolysishasadvancedtolargerandlargerscaleoverthelasttwentyyears,progressingfromsystemsof1kgH2/dayorlesstoseveralhundredkg/day.Whileleveragingthesamebasicmanufacturingprocessesandtechnology,scaleuphasdrivendown the capital cost per kgof hydrogenbyover 80%. PEMelectrolysis alsohas tremendouspotential for continuing cost reduction, leveraging system and manufacturing scaling laws as well as leveragingadvancements in PEM fuel cellmaterials,manufacturing, and analysis tools. Order-of-magnitude improvements insomeofthehighestcostelementsareeasilyachievable.Thetechnologyelementsareknown,butneedtoberefinedandvalidatedinamanufacturingenvironment, includingmodificationsinmaterialsandmethodsoffabrication.Thispresentation will focus on the need to leverage existing clean energy technologies in the near term to serve themegawattandgigawattscale,asbuildingblocksandbridgestofuturetechnologies.

ProtonOnSite'sLineofCommercialPEMElectrolysisProducts


28


KeyPerformanceIndicatorsforMW-scalePEMwaterelectrolyzers

P.Milleta

aParis-SaclayUniversity,InstitutdeChimieMoléculaireetdesMatériauxd’Orsay,91405Orsay,cedex,[email protected]

Summary.Emergingwaterelectrolysismarketsarecallingforsystemsofincreasingsize.Comparedtohydrogenfrommethane(viaSMR,evenwhenCCSisincluded),electrolytichydrogenispenalizedbyahigherenergycostwhich,onMWsystemsandabove,isexpectedtoaccountasmuchas80%oftheproductioncost.AccesstolowcostkWhisthereforeakeyfactortomakewaterelectrolysiscostcompetitive.Intheframeoftheenergytransition,increasingamountsofintermittent electric power are expected to transit onnational electricity grids.Grid services and the energy trademarketareexpectedtoincreasesignificantly.OpportunitiestopurchaselowcostelectricalkWh(includingatnegativeprice)areappearingbutfromtheengineeringviewpoint,theresultingconstraintistheneedformoreflexibleandmorereactivewaterelectrolysisplants.Thiscouldinturnhavedeleteriouseffectonprocessefficiency,safety,durabilityandcost.Thesituationmightbeevenworseiftheelectrolysisplantisdirectlypoweredbymoreintermittentwindorsolarpower sources. Among three main water electrolysis technologies (alkaline, PEM and steam electrolysis), protonexchangemembrane(PEM)isconsideredasverypromisingandverycapabletosatisfythesenewoperatingconstraints.ThepurposeofthiscommunicationistodiscussasetofkeyperformanceindicatorsthatcanbeusedforthequalificationofMW-scalePEMwaterelectrolysersforgridservices.

Abstract.Therearecurrentlythreemainmarketsofdifferentmaturityforelectrolytic(fromwater)hydrogen:(i)H2asachemicalformiscellaneousapplicationsintheindustry;(ii)H2asanenergy-vectorformobilityapplications(viaon-boardpowergenerationbyelectrochemicalcombustionofhydrogeninairusingfuelcells);(iii)H2asanenergy-vectorfor power-to-gas and large scale energy storage.Whereas commercial activities are mostly supported by the H2-chemicalmarket,mobilityapplicationsseemandendlessshort-termrealityandpower-to-gasapromisingElDoradofortechnologymanufacturers.

Consideringthefactthat,forlargewaterelectrolysers,thecostoftheH2-kgisincreasinglydeterminedbythecostofelectricity,expectedprogressinprocessefficiency,althoughhighlydesirable,willnotbesufficienttomakeelectrolytichydrogen cost competitive with incumbent technologies. Cheap kWh is required, as has always been. The energytransitionandthemassiveirruptionofintermittentelectricitymightoffersomedeterminingopportunitiestothosewhowillbeabletoputonthemarketappropriatelylargeandflexibletechnologies.Also,downstreamoperatingconstraints(e.g.periodicalproductionofcompressedhydrogen)mayinterferewithinputpowerconstraints,requiringcustomizedtechnologies that still need to be developed. Whereas most commercial PEM water electrolysis applications aredesignedforstationaryoperation,ahigherflexibilitythatwouldnotpenalizeefficiency,safety,durabilityandcostposessomeinterestingchallengestotheelectrochemicalengineerinchargeofR&Dactivities.Here,thewaterelectrolysisplant as a whole (including the electrochemical reactor but also a set of ancillary equipment such as the waterpurificationunit,thegaspurificationunit,etc.)needsadaptation.

The purpose of this communication is first to review the opportunities and constraints imposed by emerging gridservices,thentopresentanddiscusskeyperformanceindicators(KPI)thatcanbeusedforthecharacterizationofMW-scalePEMwaterelectrolyzerswishingtooperateonsuchmarkets.ThefirstKPIofinterestistheefficiencyintransientconditionsofoperation.AdetaileddescriptionofefficiencycalculationinvaryingT,Pconditionswillbepresented.ThesecondKPIisprocessflexibility,i.e.theabilityofthewaterelectrolysisplantasawholetooperateondemandtoanypowerloadsetbetweenzero(off-grid)andmaximumpower(fullon-grid).ThethirdKPIisprocessreactivity,i.e.therateatwhichthesettingpowercanbereached.ThefourthKPIisthesafetyofoperation.Ramp-upandramp-downloadprofilesareexpectedtochangegascompositionandto induceacceleratedageingprocesses.Bothmayraisesafetyissuesduringoperation.ThefifthKPIisdurability,i.e.theabilityofthewaterelectrolysisplanttooperateinaflexiblewayonasufficientlylongperiodoftimetomaintaincapexalignedwithmarketrequirements.


29

Some results that demonstrate thepotential of PEMwater electrolysis for such applicationswill bepresented andfinally,somedevelopmentchallenges(intermsofmaterialbutalsointermsofwaterelectrolysisplantasawhole)willbehighlighted.


BusinessOpportunitiesforMWelectrolysisandrelatedRequirements

ManfredF.Waidhas

SiemensAG,HydrogenSolutions,91058Erlangen,[email protected]

Summary.Hydrogenisanenablertopushforwardtheenergytransitioninaneconomicallyviablemanner.Siemensviewonthistopicisprovidedandsomeexamplesalongitsroadmaparedescribed.

Abstract. IftheworldwidecommitmenttoCO2-reductionremainsvividtheforcedextensionofrenewableenergies(RE) ismandatory. The big challenge in this context is the volatile character of its power generation leading to anincreasingmismatchbetweengenerationanddemand.Thestorageofexcessproductionwillbecomeessentialinthefuture inorder toenableviablebusiness cases.Theestimatedstoragedemand inmanycountrieswith relatedCO2reductionplanswillbeintheTWhrange.

Amongthethreeoptionsforlarge-scalestorage–pumpedhydro,compressedairandhydrogen-hydrogenistheonlyviableoptiontoaddresscapacities>10GWh.Moreover,itisamultifunctionalchemicalenergycarrier.Itprovidestheoptiontobere-electrifiedwithoutCO2emissions.Butitisalsoavaluablerawmaterialinchemicalindustrywithamarketvolumeofapprox.100billionUSD.

CouplingtheEnergysectorwiththeindustrialandmobilityworldistherelevantkeytoproceedintheenergytransitionandtomakeitaffordable.Enablingcomponentofthehydrogenstorageconceptistheelectrolyzersystem.Itmust–amonganumberofotherfeatures–bereliableunderindustrialworkingconditionsanditsoverallefficiencymustbeoptimizedforintermittentoperation.WiththeintentiontoprovidesolutionsforfutureenergygridsSiemensdevelopedthePEMsystemcalled“SILYZER”.

Thepresentationwillpointoutrelevanttechnicalrequirementsandnecessaryframeconditionforacompetitivemarketenvironment.InformationisgivenonthemodularSilyzer200system,successfullyoperatedat‘EnergieparkMainz’andthenewSilyzer300development.Itismodularaswellandplannedtocoverthepowerrangeofapprox.10to100MW.

Fig:Greenhydrogenhasabroadvarietyofpotentialapplications


30

AbstractNo.8

Stack design for a Megawatt scale PEM electrolyser, and overview of the FCH-JU project MEGASTACK

MagnusThomassenaaSINTEFMaterialsandChemistry,Oslo,Norway

[email protected]

Summary. The FCH-JU project MEGASTACK is developing a PEM electrolyser stack design for MW-sized waterelectrolysers.ThispresentationwillgiveanupdateofthemainachievementsandresultsfromtheMEGASTACKprojectfromfundamentalaspectsoftransportinporoustitaniumsinters,twophaseflowmodellingtodesignandcostelementsofthefinalstackdesign.

Abstract.IntheMEGASTACKprojectwetakeadvantageoftheexistingPEMelectrolyserstackdesignsofITMpoweraswell as novel solutions in the low-cost stackdesign concepts developedand further refined in the FCH-JUprojectsNEXPELandNOVEL. Inorder to successfullyup-scale thedesignconcept froma10-50kWtoaMW-sized stack,anintegratedtwo-phaseflowandstructuralmechanicsmodellingapproachhasbeenappliedtogetherwithoptimizationof stack components such as MEAs, current collectors and sealings which are important for stack scale up. Thedevelopmentactivitieshavefocusedonexistingsolutions,alreadyproveninkW-sizedelectrolyserstacks,ratherthanaimingtousecompletelynew,unprovenconceptsandmaterials.Thestackdesignwillhaveeaseofmanufactureandstackassemblyasamajorgoal,withnecessaryqualitycontrolprocessesandrobustsupplychainsforcomponents.

To reach these ambitious objectives, MEGASTACK has developed and will demonstrate an enhanced stack designessentialforcost-competitive,efficientanddynamicPEMelectrolysissystemsthroughthefollowingkeyconcepts:

• Thestackdesignprocesswillhaveanintegratedapproach,involvingstackmanufacturers,componentandMEAsuppliersaswellasPEMelectrolyserexpertsfromresearchinstitutes.

• Evaluationandadaptationofexistingsolutionsandcommerciallyavailablecomponentsforuseinlargeformatstacksandincreasedeaseofstackassemblybythereductionofstackpartcount.

• Advancedmultiphaseflowmodellingcoupledwithmultiphysicsmodelsforelectrochemicalkinetics,heatandmomentumtransportwillbeusedasdetaileddesigntoolsforcellandstackcomponents.

• Implementationofqualitycontrolmeasuresandsupplychainevaluationofallcomponentswillbeperformedinordertoreducecostsandminimisetechnologyandmanufacturingrisks


31

AbstractNo.9

Techno-EconomicModelingofRenewableEnergyHydrogenSupplySystemsbasedonWaterElectrolysis

ØysteinUlleberg

InstituteforEnergyTechnologyP.O.Box40,NO-2007,Kjeller

[email protected]

Summary.Thereisagrowinginterestforusingrenewablepowertorunwaterelectrolyzersforon-siteproductionofhydrogen for supply to variousenergy, industrial, and transportapplications. Howcan such systemsbecomecost-efficient?Atechno-economicmodellingtoolhasbeendevelopedinordertotrytoanswerthisquestion.

Abstract.On-sitesmallwaterelectrolyzer systemsaremodular,andcanbedeveloped formanydifferentsizesandcapacities.Severalinternationalcompaniessupplyon-sitehydrogenproductionsystem,andthetechnologyreadinesslevelishigh(TRL7-9).However,onasystemlevelitisstillnecessarytodevelopmoreenergyandcost-efficientsolutions.Inordertoachievethisitwillbenecessarytobothreducetheamountofmaterialsusedinthekeycomponents(e.g.cellsandstacks)andtodevelopmoreefficientoverallbalanceofplants (e.g.drying,compression,andstorage,andelectricalsystems).

Asimplifiedequationbasedtechno-economicmodellingtoolhasbeendevelopedinEES(EngineeringEquationSolverprogram).Thisprogramcanadjustedandusedtoaccessthetechno-economicsofawiderangeofrenewablepowerbasedwaterelectrolyzerssystems,includinghydrogencompression,storageanddispensingsystems.Themodelsarebasedonup-to-datetechnicalperformancedataobtainedfromleadingPEMandalkalinewaterelectrolyzerandotherhydrogentechnologysuppliersaroundtheworld,andcostdatacollectedinvariousprojectsconductedatIFEoverthepastfewyears.

Themodellingtoolhasbeenappliedintoevaluatetheeconomicviability(businesscase)forbothlarge-scale(4-5MW)andsmall-scale(150-200kW)hydro-electricpowerbasedwaterelectrolysissystems.Thetechno-economicviabilityofasystem(Figure)connectedtoasmall-scalehydro-electricpowerplantinNorwayispresented.

Figure–Systemschematicofthewaterelectrolyzerandhydrogensupplysystemevaluatedinthisstudy


32


TheOxygenEvolutionReaction:TheEnigmainWaterElectrolysis

ThomasJ.Schmidta,baElectrochemistryLaboratory,PaulScherrerInsitute,CH-5232VilligenPSI,Switzerland

bLaboratoryofPhysicalChemistry,ETHZürich,CH-8093Zürich,[email protected]

Summary. In order to gain bettermechanistic understanding for the oxygen evolution reaction in both acidic andalkaline environment, nanoscaled oxides are investigated by electrochemical methods and by operando x-rayabsorption spectroscopy. Important insights could be gained on the surface self-assembly of the catalyst surfaceresponsibleforhighactivity.

Abstract.Oxygenelectrodesareplayingakeyroleinelectrochemicalenergyconversiondevicessuchasfuelcellsandwaterelectrolyzers.Inbothacidicandalkalineenvironment,boththeoxygenreductionandoxygenevolutionreaction(ORRandOER),respectively,arelimitingtheoverallenergy/voltageefficiencyduetoitssluggishkinetics.[1,2]

Whereasinacidicenvironment,mainlypreciousmetaloxidesareusedtocatalyzetheOER(e.g.,IrO2),thevarietyofpossiblecatalystsinalkalineelectrolyteissignificantlyincreasedandmanymetaloxidebasedsystemscanbeemployed.Generallytheoxygenevolutionmechanismisonlypartlyunderstoodindependentoftheelectrolyteenvironmentandmaterialused.InordertohelptounderstandtheunderlyingmechanismfortheOERandtosupporttheexperimentalresults,veryoftencomputationalmethodsareused,mainlyusingdensityfunctionaltheory(DFT)calculations.Similarapproachesarealsousedforgaininginsightsintocatalyststabilitiesunderoperationalconditions.

Inthistalk,someofyourrecentfindingsonnobleandnon.noblemetalcatalysts,i.e.,nanoscaledIrO2andnanoscaledperovskiteswillbepresented.ByemployingoperandoX-rayabsorptionspectroscopy(bothXANESandEXAFS),importantinsightscouldbegainedwithrespecttotheoxideelectronicstructureandthelocalcatalyststructurehelpingtobetterunderstandtheunderlyingmechanismfortheOER.

Acknowledgement.ThisworkissupportedbytheSwissNationalScienceFoundation,theSwissCompetenceCenterforEnergyResearch(SCCER)Heat&ElectricityStorage,theSwissFederalOfficeofEnergyandtheCompetenceCenterEnergy&MobilitySwitzerland.

References

[1]A.Rabis,P.Rodriguez,T.J.Schmidt,ACSCatal.,2012,2(5),864–890

[2]E.Fabbri,A.Habereder,K.Waltar,R.Kötz,T.J.Schmidt,Cat.Sci.Tech.,2014,4,3800-3821


33

AbstractNo.11

OxygenEvolutionReactiononPerovskites:ACombinedExperimentalandTheoreticalStudyofTheirStructural,Electronic,andElectrochemicalProperties

XiCheng,aEmilianaFabbri,aMaartenNachtegaal,bIvanoE.Castelli,cMarioElKazzi,aRaphaelHaumont,dNicolaMarzari,candThomasJ.Schmidtac

aElectrochemistryLaboratory,PaulScherrerInstitut,5232Villigen,SwitzerlandbPaulScherrerInstitut,5232Villigen,Switzerland

cTheoryandSimulationofMaterials(THEOS)andNationalCentreforComputationalDesignandDiscoveryofNovelMaterials(MARVEL),ÉcolePolytechniqueFédéraledeLausanne,1015Lausanne,Switzerland

dSP2M,ICMMO,UniversitéParis-SudXI,91405Orsay,FranceeLaboratoryofPhysicalChemistry,ETHZurich,8093Zurich,Switzerland

[email protected]

Summary.The correlationbetween theOERactivitywithonephysico-chemicalmaterials propertypresents alwayssomedeviationpoints,indicatingthelimitofthe2-Dimensioncorrelation.Hence,wetrytocorrelatetheOERactivitywithseveralphysico-chemicalmaterialspropertiesatthesametimeandleadingtoa3-Dimensioncorrelation.

Abstract.PerovskiteOxides(ABO3)withalkalineorrare-earthcationsintheA-siteandfirstrowtransitionmetalcationsintheB-sitehaveshownthepotentialsofbeingviableoxygenelectrodecatalystsinalkalinesolution1.Furthermore,itwasdemonstratedthattheirphysical-chemicalpropertiesaswellastheircatalyticactivitycanbesignificantlyinfluencedbysubstitutionorpartialsubstitutionoftheAand/orB-sitebyotherelementsgiving(AxA’1-x)(ByB’1-y)O3compositions.However, it is a difficult task to find the most active oxides among the many different families of perovskites. Adescriptor-basedanalysiscanprovideapromisingapproachtopredictandidentifythemostactivematerials,sinceitcorrelatestheprospectiveelectrocatalyticactivitytoother,simplerproperties.Inthepresentwork,thecrystallographicstructure,bulkelectronicstructure,conductivityandelectrochemicalactivitytowardtheoxygenevolutionreactionfortwoperovskiteseries(La1-xSrxCoO3

2withx=0,0.2,0.4,0.6,0.8,1andLaBO3withB=Cr,Mn,Fe,Co,Ni)areinvestigatedexperimentallyandtheoretically.Experimentalcharacterizations(XRD,XAS,neutrondiffraction,ex-situelectronicconductivityandOERmeasurements)demonstratethatthevaryingoftheA-siteand B-site delivers several changes in the physicochemical properties of the considered oxides. But by combiningexperimentswith density-functional theory calculations,we show that it is possible to reliably relate some simplephysico-chemicalmaterialspropertiesincludingtheelectronicstructuretotheobservedactivitytowardstheoxygenevolutionreaction.However,thecorrelationbetweentheOERactivitywithonephysico-chemicalmaterialspropertypresentsalwayssomedeviationpoints,indicatingthelimitofthe2-Dimensioncorrelation.Hence,wetrytocorrelatetheOERactivitywith severalphysico-chemicalmaterialspropertiesat the same timeand leading toa3-Dimensioncorrelation.Thiscorrelationmightfacilitatethesearchanddesignofhighlyactiveoxygenevolutioncatalysts, inthequestforefficientanodesinwaterelectrolyzers.1.E.Fabbri,A.Habereder,K.Waltar,R.Kotz,T.J.Schmidt,Developmentsandperspectivesofoxide-basedcatalystsfortheoxygenevolutionreaction.CatalSciTechnol2014,4(11),3800-3821.

2.X.Cheng,E.Fabbri,M.Nachtegaal,I.E.Castelli,M.E.Kazzi,R.Haumont,N.Marzari,andT.J.Schmidt,OxygenEvolutionReactiononLa1−xSrxCoO3Perovskites:ACombinedExperimentalandTheoreticalStudyofTheirStructural,Electronic,andElectrochemicalProperties.Chem.Mater.2015,27,7662-7672.


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AbstractNo.12

Electrocatalysis of Oxygen-Evolution on Well-Defined Mass-Selected NiFe nanoparticles

ClaudieRoya,BélaSeböka,ElisabettaM.Fiordalisob,AndersBodina,JakobKibsgaarda,IfanStephensaandIbChorkendorffa

aSurfacePhysicsandCatalysis,DepartmentofPhysics,TechnicalUniversityofDenmarkaCenterforElectronNanoscopy,DepartmentofPhysics,TechnicalUniversityofDenmark

[email protected]

Summary.Electrocatalysisofoxygen-evolutiononwell-definedMassselectedNiFe(Ox)nanoparticleswasinvestigatedin1MKOH.Resultsobtainedshowaturnoverfrequencyamongthehighestinalkalinemedia.Thiswell-definedsystemprovideskeyinsighttowardstheoptimizationoftheelectrocatalyticactivityoftheNiFesystem.

Abstract.Water electrolysis can provide ameans to produce hydrogen using renewable electricity. The storage ofenergyusinghydrogenasfuelishinderedbythesluggishkineticoftheoxygenevolutionreaction.Inorderforthesedevicestobedevelopedonalargescale,moreactivecatalystsareneeded.NiFeoxy-hydroxidesarethecurrentstate-of-the-artcatalysts foroxygenevolution.Theoriginof theiractivity iscurrentlyunder intensedebate.Forexample,there isuncertaintywhetherthebulkorthesurface isactive. Inorderto improvethecatalysisofthisreaction, it isimportanttogainfurtherunderstandingofthefactorscontrollingtheintrinsicactivity.Tothisend,inourcurrentstudy,we investigated well-characterized model systems of NiFe nanoparticles[1-3]. We deposited mass-selected NiFenanoparticles with different sizes on polycrystalline gold substrates to create well-defined model-systems. Ourlaboratorypreviouslythisapproachtoelucidateoxygenreduction[4]andhydrogenevolution[5].

A wide range of techniques was used to characterize our model system: X-ray Photoelectron Spectroscopy, IonScatteringSpectroscopy,X-raydiffraction,SecondaryElectronMicroscopyandTransmissionElectronMicroscopy.Wetestedthecatalystselectrochemicallyforoxygenevolutionin1MKOHusingarotatingringdiskelectrodeset-up.Theactivityasfunctionofparticlesizeandinterparticledistanceswasevaluated,aswellasmeasuringthestabilityagainstcorrosion.Ourresultsshowthattheparticleshaveamongthehighest intrinsicactivityofnon-noblealkalineoxygenevolutioncatalystreported.

[1]M.K.Debe,S.M.Hendricks,G.D.Vernstrom,M.Meyers,M.Brostrom,M.Stephens,Q.Chan,J.Willey,M.Hamden,C.K.Mittelsteadt,C.B.Capuano,K.E.AyersandE.B.Anderson,J.Electrochem.Soc.,159,K165(2012).

[2]Dionigi,F.andStrasser,P.,Adv.EnergyMater.(2016)1600621.

[3]BryanM.Hunter,JamesD.Blakemore,MarkDeimund,HarryB.Gray,JayR.Winkler,andAstridM.Müller,J.Am.Chem.Soc.136(2014)13118.

[4]Hernandez-Fernandez,P.,Masini,F.,McCarthy,D.N.,Strebel,C.E.,Friebel,D.,Deiana,D.,Malacrida,P.,Nierhoff,A.,Bodin,A.,Wise,A.W.,Nielsen,J.H.,Hansen.,T.W.,Nilsson.Stephens,I.E.L.,Chorkendorff,I.Nat.Chem,6(2014)32.

[5]Bodin,Anders;Sebök,Béla;Pedersen,Thomas;Seger,Brian;Mei,BastianTimo;Bae,Dowon;Vesborg,PeterChristianKjærgaard;Halme,J.;Hansen,Ole;Lund,P.D.;Chorkendorff,Ib.,EnergyEnviron.Sci.8(2015)2991.


35

AbstractNo.13

RANEY-NIELECTRODESFORTHEALKALINEELECTROLYSISOFWATERC.I.Müllera,T.Rauscherb,B.Kiebacka,b,L.Röntzscha

aFraunhoferInstituteforManufacturingTechnologyandAdvancedMaterialsIFAM,BranchLabDresden,Winterbergstraße28,01277Dresden,Germany,

bTechnischeUniversitätDresden,InstituteforMaterialsScience,Dresden,[email protected]

Summary.Raney-Nielectrodeswereproducedviaapowdermetallurgicalrouteandelectrochemicallycharacterized.TheresultssuggestthattheformationofnickelhydridesisacrucialissueforthedegradationofRaney-Nielectrodes.AnoperatinginstructionisgiventominimizethedegradationofRaney-Nielectrodes.

Abstract.

Thegrowingenergyconsumptionandtheshortageofthefossilenergysourcesnecessitatethesearchforalternativeenergy carriers. In this regard, hydrogen is a safe and versatile energy carrier which can be produced via waterelectrolysis using renewable energy sources (“green hydrogen”). For a commercial H2-based energy cycle (mobileapplication)theproductioncostsofgreenhydrogenmustdropbelow6€/Nm³.Therefore,theCAPEXaswellastheOPEXofelectrolysershastobeimprovedbydevelopingmoreactiveandstableelectrodematerialsforthehydrogenevolutionreaction(HER).

Inthiscontributionwereporton3-dimensionalRaney-Nielectrodes,whichwereproducedandcharacterizedunderindustrialrelevantconditions(seeFigure2).Nimesheswereemployedasaporoussubstratematerial.Theporosityofthe electrode is decisive to manage the flow of evolved gas bubbles to the backside of the electrode. A powdermetallurgicalroutewasdeployedtoproducetheRaney-Nielectrodes,includingthefollowingsteps:depositionofAl-powder, formation of the Raney-Ni phases (heat treatment) and leaching in KOH solution at 353 K. Differentpowder/mesh ratios (PMR) were tested and the corresponding electrochemical properties were studied. Thegalvanostaticmeasurements (GS) indicate that a highAl-powdermesh ratio (PMR) is necessary to receive a stableRaney-Nilayer.AlsotheHER-activityoftheelectrodeincreasesdramaticallywiththePMRvalue.Thisismainlyduetotheformationofaveryhighelectrochemicallyactivesurfacearea(determinedwithcyclicvoltammetry(CV)),whichgivesrisetoveryhighnumberofreactionsitesfortheHER.Ex-situinvestigationsofthecrosssectionoftheelectrodesrevealthatthemaindeactivationpathoftheRaney-Nielectrodesisthedelaminationofthecatalystlayer.Linearsweepvoltammetry(LSV)experimentssuggestthatduringtheHERtheformationofnickel-hydridesoccurs(seeFigure2b)),whichisaccompaniedwiththevolumetricexpansionoftheRaney-Nilayer.This,inturn,mightleadtothedelaminationoftheRaney-Nilayer.InthepresentationtheresultsarediscussedinmoredetailandanoperatinginstructionisgiventominimizethedegradationofRaney-Nielectrodes.

a) b)

Figure2:a)crosssectionofaRaney-Nielectrodeandb)linearsweepvoltammogramofaRaney-NielectrodeafterHER.


36

AbstractNo.14

RaneyNickelalloyelectrodesforalkalinewaterelectrolysis

AsifAnsar,RegineReissner,DanielaAguiar,TaikaiLiu,GünterSchiller

DLR,InstituteofEngineeringThermodynamics,Stuttgart,[email protected]

Summary.Alkalineelectrolysisanodesandcathodesofhighefficiencyandstabilityweredevelopedusingvacuumandatmosphericplasmaspraying.Lowcostmaterialsandasimplifiedcoatingprocessallowforcostreductions.

Abstract. Alkalinewaterelectrolysisforhydrogenproductionisawell-establishedtechniqueavailablecommerciallyinawidepowerrange.Hydrogenproductionbyelectrolysisisincreasinglystudiedasawaytosmoothenthefluctuatingpoweroutputofrenewableenergysourcesinoversupplysituations.However,sometechnologicalissuesregardingthecoupling of alkaline water electrolysis and Renewable Energy Sources (RES) remain unaddressed. The presentedresearchaimsatimprovingpresentelectrolysersforthespecificsofdirectcouplingtofluctuatingpoweroperation.Dueto the cost-effective hydrogen production by steam reforming as competition the importance of electrolyser costreduction and improving efficiency is paramount.Oneof the aspects is to develophigh-efficient electrolyserswithsuperiorcurrentdensitythatcantolerateperiodsofidlingwithoutdegradation.Electrodeswithlowcostcoatingsforthispurposearepresentedhere.Efficient electrodes are prepared by vacuumplasma spray deposition of catalyst powders at DLR onto plain nickelelectrodes.TheelectrodeswithRaney-nickel-alloycoatingsgiveanoverpotential reductionof330mVcomparedtouncoatedelectrodesthusshowinghighperformancewithlowcostmaterials.Longtermon-offtestswereperformedinhalf cells. Considering only the electrode potentials of anode and cathode together an excellent stability wasdemonstrated:after1100on-offcycles98%oftheinitialefficiencywasretained.Electrodesweretestedinhalfcellsandina300cm2alkalinesinglecell.Tofurtherreducethecostsforelectrodecoatingatmosphericpressureplasmasprayingistested.Firstresultsofthisseemquitepromissingreachingthesameperformancelevelasforvacuumplasmaspraying.TheresearchleadingtotheseresultshasreceivedfundingfromtheEuropeanUnion’sSeventhFrameworkProgramme(FP7/2007-2013)fortheFuelCellsandHydrogenJointTechnologyInitiativeundergrantagreementn°[278732]10,projectRESelyser.Seealsowww.reselyser.eu. Furthermore support by the Ministerium für Finanzen und Wirtschaft Baden-Württemberg (MFW) inLeuchtturmprojekt„Power-to-Gas“isgratefullyacknowledged.


37


RolesforHighTemperatureElectrolysisintheRapidlyChangingUSEnergyMarket

CarlStoots,PhDa

[email protected]

Summary.TheUnitedStatesenergymarkethaschangeddramaticallyoverthepastdecade.Althoughthedriversandimplementationstrategiesforwater-splitting-basedhydrogenproductionhavechanged,therestillremainssignificantinterestandneedforadvancedhydrogenproductiontechnologies.

Abstract.TheUnitedStatesDepartmentofEnergy(DOE)establishedtheNuclearHydrogenInitiativeintheyear2003tostudyhownuclearenergy(inparticular,hightemperaturegas-coolednuclearreactors)couldbediversifiedbeyondbaseloadelectricitygenerationpowerwater-splittingforlarge-scalehydrogenproduction.Atthattime,themotivationwasprimarilyenergysecurity.USpolicymakershadbeenconcernedabouttheUSdependenceuponimportedenergysinceWorldWarII.Theseconcernswerehighlightedinthe1970swhentheUSexperiencedsharplyrisingoilprices,whichinturnledtoeconomicrecessionsandinflation.Furthermore,energypunditsbegantoworryaboutaconceptcalled“PeakOil.”FirstputforwardbyM.KingHubbert,thisconceptsuggeststhatoilproductionfollowsasteepbellcurve,whereproductionrisesandthenentersapermanentdecline.HistheorysuggestedthatUSoilproductionwouldpeaksometimeinthelate1960sandthendecline–whichendedupbeingpartiallycorrect.DroppingUSoilproductionwasthoughttopotentiallycausetheUStobeincreasinglydependentonotherproducers,leadingtoissuesofdomesticenergy security. By introducinga secondenergy currency that couldbe sustainablyproduceddomestically, theUSgovernmenthopedtoavoidover-dependencyuponforeign,andpotentiallyhostile,entitiesforenergy.

However,insteadofUSoilproductioncontinuingtodrop,productionbegantorisesteadilyin2009duetonewadvanceddrillingtechnologies(horizontaldrilling/hydraulicfracturing)andhencenewaccesstopreviouslyinaccessiblereservesofshaleoilandgas.FrackinghashadaprofoundimpactupontheUSenergymarket.TheHISMarkitestimatedthatfracking“increaseddisposableincomebyanaverageof$1200perUShouseholdin2012”andanaveragereductioninelectricity costs of 10%. In parallel to the growth of fracking, the US has also been experiencing an explosion ofrenewableenergy,primarilywindandsolar.Bothcoalandnuclearpoweraretraditionallylarge,baseload,electricitygenerators which experience increased costs and maintenance when forced to cycle in response to renewable(nondispatchable) energy availability. Nuclear operators in theUS are now struggling to stay open,more than sixnuclear reactorshaverecentlyshutdown,and15to20moreplantsareat riskofprematureshutdown in thenextdecadeduetonaturalgaseconomics.Andcoal-basedelectricityproductionhasdroppedfrom53%oftheUSenergymixin1993to33%in2015.

Despite the dramatic changes in the US energy portfolio, hydrogen via high temperature water splitting is stillconsideredanimportantlong-termenergystrategyandcontinuestogenerateinterestattheUSDOE.Technologiessuchhightemperatureelectrolysiscanbe linkedtonuclearreactorstoenhancetheireconomiccompetitivenessviadiversification beyond baseload electricity generation. High temperature electrolysis can enhance grid stability byabsorbing excess electricity via hydrogen production and storage. The same technology can provide additionalelectricitygenerationcapacitywhenrenewablesarenotavailable.Hightemperatureelectrolysiscanprovidehydrogento upgrade oil, and convert low value carbon sources to higher value carbon products (synfuels, plastics, etc.).Ultimately,hydrogenfromwaterisbeingstudiedasthenextmajortransportationfuel,poweringfuelcellvehicles.


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AbstractNo.16

SolidOxideElectrolysisforGridBalancing:RecentAchievementsandFutureChallenges

MingChena,JensValdemarThorvaldHøgha,PeterBlennowb,AnneHaucha,KarenBrodersena,XiufuSuna,ChristopherR.Gravesa,SimonaOvtara,KarstenAgersteda,SebastianMolina,XiaofengTonga,JanetJonnaBentzena,PeterVang

Hendriksena,andMogensBjergMogensenaaDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,Roskilde,Denmark

bHaldorTopsoeA/S,Kgs.Lyngby,[email protected]

Summary.

SolidoxideelectrolysisisapromisingtechnologyforenergystorageandsyntheticfuelproductionandithasauniquepotentialforgridregulationintheDanishpowersystem.InthispresentationresultsfromtherecentForskELprojectscoordinatedbyDTUEnergyondevelopingtheSOECtechnologywillbepresented.

Abstract.

Globallytheamountofelectricitygeneratedfromrenewableenergysourcesisincreasing.Tointegratehighamountoffluctuatingenergyintotheexistingenergygrid,efficientandcostcompetitiveconversionofelectricityintootherkindsofenergycarriersisneeded.Solidoxideelectrolysis(SOE)hasthepotentialtobecomeakeytechnologyinenablingthisintegration.Withsolidoxideelectrolysiscells(SOECs),electricalenergycanbeconvertedtochemicalenergyandstoredasH2orsynthesisgas(syngas,CO+H2)viahightemperatureelectrolysisofsteamorco-electrolysisofsteamandCO2.H2andsyngascanbefurtherprocessedtoavarietyofsyntheticfuels,whichmaybestoredandlatereitherreconvertedintoelectricityorusedinthetransportationsector.Withinthelastdecade,DTUEnergycoordinatedandparticipatedinanumberofForskELprojectsfundedbyEnerginet.dk,ondevelopingtheSOECtechnologytogetherwithHaldorTopsoeA/S.InthispresentationresultsfromtherecentForskELprojects(ForskEL2013-1-12013“SolidOxideElectrolysisforGridBalancing”andForskEL2015-1-12276“TowardsSolidOxideElectrolysisPlantsin2020”)willbegiven.ThefocuswillbeonperformanceanddurabilityofdifferentgenerationsofSOECcellsandstacks, togetherwithpost-mortemanalysis results. Latest results on using SOEC stacks for grid balancing based on real-world wind profile will behighlighted.PotentialproblemsintermsoflifetimelimitingdegradationphenomenainSOECoperation(bothatthecelllevelandatthestacklevel)willbediscussedindetailbasedonownfindingsaswellasliterature.Finally,someofthechallengesfacedinthefuturedevelopmentofSOECcells,stackcomponentsandstackswillbepresented.


39

AbstractNo.17

Operationandperformanceoftubularprotonceramicelectrolysers

EinarVøllestada,RagnarStrandbakkea,DustinBeaffbandTrulsNorbyaaUiOUniversityofOslo,DepartmentofChemistry

[email protected]

Summary.TubularprotonceramiccellsbasedonY-dopedBa(Zr,Ce)O3aredevelopedwithanoveldoubleperovskitesteamelectrode(Ba1-xGd0.8La0.2+xO6-δ).State-of-the-artperformanceisachievedat600°Cwithatotalcellresistanceof3.5Ωcm2anda totalelectrode resistanceof1.5Ωcm2.Optimizationof theelectrolyte layerandadhesionbetweenelectrolyteandelectrodelayersshouldgiveroomforfurtherimprovementofthesecellstoachievetherequiredtotalcellresistanceswellbelow1Ωcm2.

Abstract.

Withtherecentintroductionofhydrogen-fuelledvehiclesinmajormarketsthereisanincreaseddemandtodevelopnewcost-efficienttechnologiesforcleanandrenewablehydrogenproduction.Hightemperatureelectrolysers(HTEs)mayproduceH2efficientlyutilisingelectricityfromrenewablesourcesandsteamfromsolar,geothermal,nuclear,orindustrial plants. The traditional solid oxide electrolyser (SOE) leaveswetH2 at the steam side. In contrast, protonceramicelectrolysers(PCEs)canpumpoutandpressurizedryH2directly.Further,thedangerofdelaminationofoxygenelectrodesduetoO2bubblesinSOECsisalleviatedinPCECs.Literaturereportsontheuseofvarioussolidsolutionsofthe BaZrO3-BaCeO3 system (BZCY) as the electrolyte, with promising current densities. However, relatively highpolarizationresistanceoftheO2/H2O-electrodeandnon-faradaicelectronicleakagecurrentsarechallengesthatarenotproperlyunderstoodorquantitativelydescribed.

In this contribution, we investigate a cathode-supported tubular proton ceramic electrolyser cell using a 30 µmBaZr0.7Ce0.2Y0.1O3-δelectrolytewithaNi-BZCYcompositeasthecathode(H2-electrode)andthedoubleperovskiteBa1-xGd0.8La0.2+xO6-δ(x=0-0.5)astheanode(H2O-O2electrode).Current-voltagecharacteristicsandhydrogenproductionratesaremeasuredasafunctionofsteampressure(pH2O=0.5-4bar)andpO2inthetemperaturerange500-700°C.Combined with electrochemical impedance spectroscopy under electrolysis operation we are able to describe thefunctionaldependenciesoftheelectrodesandtheelectrolyteseparately.

Thebestperformanceat600°CwasachievedusingaBa0.7Gd0.8La0.5O6-δelectrode,andoperatingthecellat1.4Vforacurrentdensityof250mAcm-2with4barsteamintheanodecompartment.ThisisthebestPCEperformancereportedinliteraturetodate.Withatotalelectrodepolarizationresistanceof1.5Ωcm2,mostofthevoltagedropthroughthecellisduetoohmicresistancesintheelectrolyteandcurrentcollectors,whichshouldbecentralinfurtherimprovementofPCEs.

Acknowledgments

FinancialsupportbytheSpanishGovernment(GrantsSEV-2012-0267andENE2014-57651)andbytheEUFP7FuelCellsandHydrogen(FCH)JointTechnologyInitiative(JTI)undergrantagreementn°621244(“ELECTRA”).


40

AbstractNo.18

FabricationandCharacterizationofMetal-supportedSolidOxideElectrolysisCells

FengHana,AzizNechachea,RobertSemeradbandRémiCostaaaGermanAerospaceCenter(DLR)

InstituteofEngineeringThermodynamicsPfaffenwaldring38-40,D-70569Stuttgart

bCeracoCeramicCoatingGmbHRote-Kreuz-Str.8,D-85737Ismaning

[email protected]

Summary.

Metal-supportedsolidoxideelectrolysiscell

La0.1Sr0.9TiO3-α(LST)compositefuelelectrode

Gadoliniumdopedceria(GDC)/yttrium-stabilizedzirconia(YSZ)bilayerthin-filmelectrolyte

Abstract.Solidoxideelectrolysiscells(SOECs)belongtothemostefficientandcost-effectiveelectrochemicaldevicesfortheenergystorageapplicationviapowertogas(P2G)concept. Intermittentenergyinformofelectricityorheatfromrenewablesourcescanbestored long-termly inthemagnitudeofGWhlevelaschemicalenergy inH2andCOthrough the electrolysis process occurs in SOEC systems. In comparison to conventional anode-supported andelectrolyte-supportedfullceramiccells,metalsupportedcellshasmanyadvantages,suchasreducedmanufacturingandmaintenancecost,faststart-upfeatures,excellentmechanical,thermalandredoxcyclestability,andetc.Inthiswork, novel metal-supported cells were fabricated on robust porous ferritic steel. Nickel free composite made ofLa0.1Sr0.9TiO3-α(LST)andgadoliniumdopedceria(GDC)wasappliedasfuelelectrodematerial.3µmthickthin-filmbilayerelectrolyteofGDC/yttrium-stabilizedzirconia(YSZ)waspreparedbyacombinationofphysicalvapourdeposition(PVD)andwetceramicprocessing.ThefuelelectrodeandLa0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)airelectrodewerebothdepositedbyscreen printing. The gas-tightness of the electrolyte was monitored by differential air leakage tests at roomtemperature.HalfcellswithlowleakageratewereselectedandloadedwithnickelnanoparticlesascatalystsintotheLST-GDCbackbonestoimprovetheelectrochemicalperformanceofthefuelelectrode.Cellsweretestedunderfuelcellmodeandelectrolysismode,respectively.Performanceandagingcharacteristicsduringoperationwereanalysedbyelectrochemicalimpedancespectroscopy(EIS)andchronopotentiometry.Subsequently,thepostmortemanalysiswasappliedtofacilitatetheunderstandingofthedegradationfeaturesandmechanismsspecifictotheelectrolysisoperationofthemetal-supportedcells.


41

AbstractNo.19

SolidOxideElectrolyserCellsoxygenelectrodebasedoninfiltratednanocompositemesoporousmaterials

M.Torrell,E.Hernández,F.Baiutti,A.Morata,A.Tarancón

CataloniaInstituteforEnergyResearch(IREC),DepartmentofAdvancedMaterialsforEnergyJardinsdelesDonesdeNegre,1,08930SantAdriàdeBesòs,Barcelona,Spain

[email protected]

Summary.OxygenelectrodefunctionalactivelayersforSolidOxideElectrolysisCells(SOEC)supportedonfuelelectrodewere fabricated employing mesoporous Ce0.8Gd0.2O1.9 (CGO) material as ceramic scaffold infiltrated withLa0.6Sr0.4Co0.2Fe0.8O3(LSCF)asthecatalyticactivephase.Electrolysisandco-electrolysisatmospherecompositionswereusedfortestingitsperformanceandstability.

Abstract.TheconditionsofSOECoperationaredemandingintermsofelectrodematerialsperformanceandstability.Forthisreasontheattentionofthepresentworkhasbeenfocusedinthedevelopmentoffunctionallayersforoxygenelectrodes,basedonnanostructuredcompositematerialswhichpresentahighdensityoftriplephaseboundary(TPB)thatwillleadtobetterlongtermstabilityandcatalyticactivity[1].Mesoporousnanocompositesarepresentedasanalternativematerialforelectrodesfunctionallayerbecausetheypresenthighsurfaceactivearea,thermalstabilityatintermediatetemperatures(500-750°C)andtheinterpenetrationbetweentheionicconductiveceramicscaffoldandtheactivecompounds,ensuringthepercolationbetweenbothnets[2].Inthiswork,fuelelectrodesupportedcells(Ni-YSZ)withYSZelectrolyteweretestedusingoxygenelectrodesbasedonCGOmesoporousmaterialsinfiltratedwithLSCFgeneratingmixed ionic-electronic conductors (MIEC)electrodes [3].CGOmesoporousmaterialwas synthetizedandcharacterizedbydifferenttechniquesasscanningelectronmicroscopy(SEM)andBrunauer-Emmett-Teller(BET).Theattachment temperature of mesoporous CGO to zirconia electrolyte was optimized by electrochemical EISmeasurements of symmetrical cells. An automatic airbrushing system has been used to deposit CGOmesoporousmaterialbywetpowersprayingtechnique.FabricatedmesoporousoxygenelectrodebasedSOECweretestedunderdifferentelectrolysisandco-electrolysisatmospheresandcharacterisedbyelectrochemicalmeasurements.ProducedmixturesofgaseswereanalysedbygaschromatographyandthemicrostructureswerestudiedasfabricatedandpostoperationbySEMtechniques.TheresultsofthemesoporousbasednanocompositecharacterisationandoftheSOECcellsareusedfordemonstratingtheimprovementinperformanceandstabilityofSOECbasedonmesoporousmaterials.

Figures:(a)TEMimageofdopped-Cemesoporouspowder(b)SEMimageofcrosssectionshowingthecompositionofcharacteristiclayersconstitutingthefuelsupportedcellbasedonLSCFinfiltratedCGOmesoporousoxygenelectrode.

References.[1]P.Moçoteguyetal.Areviewandcomprehensiveanalysisofdegradationmechanismsofsolidoxideelectrolysiscells.Int.J.HydrogenEnergy38(2013)15887-15902.[2]Almar,L.etal.High-surface-areaorderedmesoporousoxidesforcontinuousoperationinhightemperatureenergyapplications.J.Mater.Chem.A2(2014)3134-3141.[3]DingD.etal.EnhancingSOFCcathodeperformancebysurfacemodificationthroughinfiltration.EnergyEnviron.Sci.,7(2014)552-575.

AcknowledgementsTheresearchleadingtotheseresultshasreceivedfundingfromECoproject.


42


ThedevelopmentandimplementationofIrbasednanowiresasoxygenevolutionelectrocatalysts

ShaunM.Alia,1,SarahShulda,2ChilanNgo,2SvitlanaPylypenko,2andBryanS.Pivovar1

1ChemicalandMaterialsScienceCenter,NationalRenewableEnergyLaboratory,Golden,CO804012DepartmentofChemistry,ColoradoSchoolofMines,Golden,CO80401

Bryan.Pivovar@nrel.govSummary.IrbasednanowireshaveshownpromisefortheirpotentialtoenablelowercostPEMelectrolyzersbyhavinghigherperformanceandmassactivitycomparedtotraditionalIrnanoparticles.

Abstract.Waterelectrolysisoffersextraordinarypotentialasaroutetocouplerenewable(sustainable)resourceswithtransportationandindustrialneeds.Notonlywouldhydrogenproducedrenewablehelpimprovesocietalissuessuchasgreenhousegasemissionsandair/waterquality,butitwouldalsoprovidebenefitsinpowergenerationload/demandmismatchandresiliency/reliability,whiledecreasingwaterrequirementsoftheentireenergysystem.Additionally,suchsystemsenabledomesticenergysourcestobemorewidelyemployed. Oftenthese issuesareconsideredonlyasasingleadvantage,howeverthepositiveattributesofwaterelectrolysisaremorefavourablewhenviewedacrossenergysectorsfortheirsynergisticadvantages.Inordertoimprovethecommercialcompetitivenessofhydrogenfromwaterelectrolysis, capital cost reductionsof systemsareakey concern. PEMelectrolyzersoffer significantpotential,butrequirerelativelyhighloadingsofIr(ametalwithevenlowernaturalabundancethanPt).WhilealternativestoIrmaybepossibleandbeingpursued,improvementsuponIrcouldallowverylowamountstoberequired.

WehaveinvestigatedIrnanowiressynthesizedfromNiandConanowiretemplatesfortheirapplicabilityasadvancedelectrolysis candidates. Thiswork has built onprevious studies of our groupdeveloping Pt nanowires for fuel cellapplications.1WehavefoundthatIrbasednanowiresoffersignificantbenefitintermsofactivity(~10ximprovement)anddurabilitycomparedtoIrnanoparticles.Whilemostofoureffortshavefocusedoncatalystdevelopmentandex-situ testing, the performance advantages of these systems has also been shown in electrolysis cell testing. ThispresentationwillfocusontheoptimizationofIrConanowiresandacomparisonbetweenIrCoandIrNinanowiresusingcommercialIrnanoparticlecatalystsasbaselinecomparisonmaterials.

Refs

1. S. M. Alia, S. Pylypenko, K. C. Neyerlin, D. A. Cullen, S. S. Kocha and B. S. Pivovar, ACS Catalysis, 2014, 4, 2680-2686.


43

AbstractNo.21

TheoxygenevolutionatIrxRu1-xO2producedbyhydrolysissynthesis

AnitaRekstena,b,HeidiThuva,FrodeSelanda,andSveinSundeaaDeptMatSciEngng,NTNU,Trondheim,Norway

bCurrentaddress:IFE,Kjeller,[email protected]

Summary.

Reactionorderswereobtainedfor theoxygen-evolutionreaction forsolidsolutionsof iridiumandrutheniumoxidemadebythehydrolysismethod.Theresultswerefullyconsistentwiththeelectrochemicaloxidepath.

Abstract.

Due to the highly acidic environment to which electrocatalysts are exposed in PEM water electrolysers, possiblecatalysts for the oxygen evolution reaction (OER) are in practice quite limited. The catalysts exhibiting the highestactivity towards theOER are RuO2 and IrO2, rutheniumoxide beingmore active than iridiumoxide, but alsomoreunstable1.Mixing of these two oxides is therefore often performed in order to achieve both an active and stablecatalyst1-4.Asignificantissueinthiscontextishowandtowhichdegreethevariouselements,forexampleIrandRu,inthesecatalystsinteract.

Wefoundinapreviouswork3thattheelectrocatalyticactivityofIrxRu1-xO2solidsolutionsappeartobeadditive,i.e.theactivityissimplythesumoftheiridiumactivitymultipliedbyxandtherutheniumactivitymultipliedby1-x.However,such an interpretation rests on an appropriate interpretation of the polarization curves, which is frequentlycompoundedbygasevolutionattheelectrodes.However,themoreaccuratethemodelforthereactionmechanismthebettertheinterpretationofactivitydataforbimetallicoxidesforcatalysisoftheOERinPEMwaterelectrolysers.Todistinguishbetween the largenumberofmechanismsproposed for theOER5-7under thesecircumstances, reactionordersareausefulsupplementtoTafelslopesfortheanalysis.

Inthisworkwepresenttheresultsofamechanisticstudyoftheoxygenevolutionreaction(OER)performedforIrxRu1-xO2,x=1,0.6,0.3and0,preparedbythehydrolysissynthesis.TheoxideswerecharacterizedbyX-raydiffraction,cyclicvoltammetryandsteadystatepolarizationmeasurements.TheelectrolytepHwasvariedinordertoobtainthereactionorderwithrespecttoprotons.

Thepolarization curves recordedcouldwere fitted toamodelderived for theelectrochemicaloxidepathwith theoxidationofadsorbedhydroxylionsbeingtheratedeterminingstep(rds).Theexpectedtrendsforthismechanismwiththeindicatedrate-determiningstepwithrespecttopotentialandpHwasfullyconsistentwiththeexperimentaldata.ThemodelsemergingfromthisworkwillbeimportantinanalysingtheinteractionbetweenelementsinsolidsolutionelectrocatalystsfortheOER,andappeartobeabletoreconcileobserveddifferencesintrendsinthecatalyticactivityofIrxRu1-xO2withcomposition.

References

1. E.Fabbri,A.Habereder,K.Waltar,R.KötzandT.J.Schmidt,CatalSci.Technol.4(2014)3800–38212. R.KötzandS.Stucki,ElectrochimicaActa,31(1986)1311–13163. L.-E.Owe,M.Tsypkin,K.S.Wallwork,R.G.Haverkamp,andS.Sunde,ElectrochimicaActa70(2012)158–1644. N.Danilovic,R.Subbraman,K.C.Chang,S.H.Chang,Y.Kang,J.Snyder,A.P.Paulikas,D.Strmcnik,Y.T.Kim,D.

Myers,V.R.Stamenkovic,andN.M.Markovic,Angew.ChemieInt.Ed.,53(2014)14016–140215. J.O’M.Bockris,J.Chem.Phys.24(1956)817–8276. A.Damjanovic,A.Dey,andJ.O’M.Bockris,J.Electrochem.Soc.113(1966)739–7467. J.Rossmeisl,Z.-W.Qu,H.Zhu,G.-J.Kroes,andJ.K.Nørskov,J.Electroanal.Chem.607(2007)83–89


44

AbstractNo.22

StudyofthePhysicalMorphologyandElectrochemicalCharacteristicsofOxygenEvolutionReaction(OER)IridiumBasedElectrocatalystSynthesizedwithaPolyol

MethodforPEMWaterElectrolysis

BrantA.Peppley,Parisa(Fatemeh)Karimi

DepartmentofChemicalEngineering,Queen’sUniversity,19DivisionSt.,Kingston,Ontario,K7L3N6,Canadae-mailofcorrespondingauthor:[email protected]

Summary.Anumberofsupportedandun-supportedOERiridiumbasedelectrocatalystsweresynthesizedusingapolyolmethod.Theelectrocatalystsandthesupportswerecharacterizedusingawiderangeofphysicalandelectrochemicalmethods.TheeffectofmorphologicalcharacteristicsoftheOERelectrocatalystandthesupportontheOERactivitywasstudied.

Abstract. The effect of heat treatment (calcination temperature) on the morphology and OER activity of Ir/ATOelectrocatalyst synthesized using the polyol method was studied. It was observed that the iridium electrocatalystsynthesizedwiththepolyolmethod,consistedof1-5nmparticlesforcalcinationtemperaturesbelow400ºCandhadanamorphousstructure.Theiridiumcalcinedattheselowertemperaturesalsohadanaverageoxidationstatelessthan+4.Calciningthecatalystattemperaturesabove400ºCupto700ºC:1)increasedthesizeoftheiridiumparticlesto30nm,2)changedthestructureofiridiumparticlesfromamorphoustocrystalline,3)increasedtheiridiumoxidationstateto+4(IrO2),4)reducedtheelectrochemicallyactivesurfaceareabyapproximately50%,and5)reducedtheOERactivityby approximately 25%; however, it had no significant effect on the physical and chemicalmorphology of the ATOsupport.

Potentialsupportmaterials:TantalumCarbide(TaC),NiobiumOxide(Nb2O5),NiobiumCarbide(NbC),TitaniumCarbide(TiC) and Tungsten Carbide (WC) were also studied. These materials were used as supports for the iridium OERelectrocatalystsandcomparedtotheATOsupportedcatalyst.TaCwasfoundtobeapromisingsupport,andincreasingits surface area by 4% improved the OER performance of the final supported catalyst by approximately 50%. ThemaximummassspecificactivityfortheTaCsupportediridiumcatalystwasoccurredataloadingof5wt%iridium.


45

AbstractNo.23

AnodecatalystsforPEMelectrolyzers:Synthesis,ActivityandDegradationAspectswithExSituandInSituCharacterization

LiWanga,*ViktoriiaA.Savelevab,ElenaR.Savinovab,TobiasMorawietzc,RenateHiesgenc,AldoS.GagoaandK.AndreasFriedricha

aInstituteofEngineeringThermodynamics,GermanAerospaceCenter(DLR),Pfaffenwaldring38-40,70569Stuttgart,Germany

bInstitutdeChimieetProcédéspourl'Energie,l'EnvironnementetlaSanté,UMR7515duCNRS-UdS25RueBecquerel,67087Strasbourg,France

cUniversityofAppliedSciencesEsslingen,Dep.ofBasicScience,Kanalstrasse33,Esslingen,73728,GermanyE-mailofcorrespondingauthor:[email protected]

Summary. Inthispresentation,ourstrategiestowarddevelopinghighperformanceoxygenevolutionreaction(OER)catalystswillbesummarized;as-developedcatalystswereinvestigatedfromnanoscaletosystemlevel;inoperandonear-ambientpressureXPStechniquewasappliedforelectrocatalysismechanismexploration.

Abstract.Protonexchangemembrane(PEM)waterelectrolysisisconsideredasoneofthemostpromisingtechnologiesforhydrogenproductionfromrenewableenergies,whichhasapotentialtopenetratethemarketinnearfutureandenabletheP2Gapplicationonawiderscale.However,oneofthemainhurdleforPEMelectrolysisistheanodecatalystbecauseofthesluggishOERkineticsanditsinsufficientdurabilityduetothehighlycorrosiveworkingenvironment.[1]Todate,Ir-basedcatalystisstilltheonlyfeasibleoptiontopromoteOERintheanodeofaPEMelectrolyzerduetoitshighactivityandconsiderablestability.Notonlythehighcostofthepreciousmetal,butalsothescarcityofIrintheearthcrustarebarriersontheroadtocommercializationofPEMelectrolyzers.Therefore,highlyactiveandstableOERcatalystsinacidelectrolytewithultra-lowIrloadingarerequiredtoaddressthisissue.

Generally,therearetwoapproachestoimproveanelectrocatalystactivity: i) increasingtheintrinsicactivityofeachactivesite;ii)increasingthenumberofactivesitesonagivenelectrode.Underthisframe,amorphousIrOxnanoparticlesarepreparedtoachieveahighintrinsicactivity,itdisplaysfive-foldhigherOERactivitythancommercialIr-black.[2]Inaddition,ahighlyactiveIrelectrocatalystderivedfromamorphousIrRuOxviaanelectrochemicalwaywasdeveloped,whichdemonstrates13timeshigherOERactivitycomparedtotherutilephaseofIrRuO2.ThestabilitywasevaluatedbyPEMelectrolyzermeasurements,showingnocellpotentialdecreaseduringca.400htest.Withthesecondapproach,DLR takeselectro-conductiveceramicsas supportingmaterials to increase theactive sitesnumber, thusachieveanimprovedIrutilization.First,IrOxwasdepositedonMagnéliphaseTi4O7showingabetterOERactivityintermsofIrmassrelative to Ir-black.[3] Further on, SnO2:Sb aerogel (developed byArmines)was introduced as a support. By takingadvantageofthehighlyporousstructureoftheaerogelsupport,Ir/SnO2:Sb-aerogelallowsadecreaseofmorethan70wt.%preciousmetalusageinthecatalyticlayer,whilekeepingthesameactivityandsignificantlyenhancingthestabilitycomparedtoitsunsupportedcounterpart.[4]

Theadvancedinoperandotechnique,near-ambientpressureX-rayphotoelectronspectroscopy(NAP-XPS),isappliedto provide insight into the potential-dependent specific chemical state of the catalysts surface and explore theirelectrocatalysisandstabilizationmechanisms.RuO2andIrRuO2wereinvestigatedunderwatersplittingconditionintheformoftheAquivion-basedmembraneelectrodeassemblies(MEA),demonstratingthatunstablehydrousRu(IV)oxideformed on the surface already before theOER regionmainly contributes to the fast dissolution of RuO2,while itsformationwashinderedbythepresenceofIrinthecaseofIrRuO2.[5]Furthermore,thesurfaceanalysisofamorphousIrOxcomparedtotherutilephaseofIrO2underthesameconditionswillalsobediscussed.

Acknowledgement. The research leading to these resultshas received funding from theEuropeanUnion's SeventhFrameworkProgramme(FP7/2007-2013)forFuelCellandHydrogenJointTechnologyInitiativeunderGrantNo.621237(INSIDE).References.[1]M.Carmo,D.L.Fritz,J.Mergel,et.al.,Int.J.HydrogenEnergy,2013,38,4901-4934.[2]P.Lettenmeier,L.Wang,U.Golla-Schindler,et.al.,Angew.Chem.Int.Ed.,2016,128,752-756.[3]L.Wang,P.Lettenmeier,U.Golla-Schindler,et.al.,Phys.Chem.Chem.Phys.,2016,18,4487-4495.[4]L.Wang,F.Song,G.Ozouf,et.al.,J.Mater.Chem.A.,2017,DOI:10.1039/C7TA00679A.[5]V.A.Saveleva,L.Wang,W.Luo,et.al.,J.Phys.Chem.Lett.,2016,7,3240-3245.


46

AbstractNo.24

Onthedesignandoptimizationofabimetallic(Co,Mn)-basedcatalystforhydrogenevolutioninacidicmedium

AliShahraeia,SimonRaneckybandUlrikeI.Kramma,baTUDarmstadt,DepartmentofChemistry,Jovanka-Bontschits-Str.2,64287Darmstadt,GermanybTUDarmstadt,DepartmentofMaterials-andEarthScience,Jovanka-Bontschits-Str.2,64287Darmstadt,[email protected]@ese.tu-darmstadt.deSummary.Inthecurrentworktheeffectofmetalspeciesinbimetallic(Co,Mn)-N-CcatalystswithpredominatelyMeN4sitesfortheHERwasinvestigated.Ourresultsindicatethatwiththeoptimizationofthemetalratioandsulfurcontentwithinthesynthesisahighlyactivecatalystforthehydrogenevolutionreaction(HER)isobtained.

Abstract.Hydrogenproducedbywaterelectrolysisispositionedamongthekeysolutionofatransitiontocleanenergyasitcanbeusedasenergycarrierwithinthetransportationsector.Nevertheless,regardingalong-termambitionofhydrogen to encourage the global investment, there are several compelling challenges. Herein, clean hydrogenproductiontechnologies,specificallyelectrolysers,attractsignificantattentionduringpastyears.However,themostcrucialistofindcheapcatalystsforwatersplittinginordertoreplacecost-intensivepreciousmetals.

Liangetal.1recentlyreportedCo-N-CcatalystswhichwereactivetowardHER,andwheretheactivitywasassignedtoCoN4activecenters.Inourrecentwork,severalMe-N-CcatalystswithvariousdifferentmetalspecieswerestudiedinordertoelucidatethenatureofHERactivityexperimentallyandtheoretically.Bimetallic(Co,Me)-N-C(Me=Mo,Mn)havebeenpresentedasthemostactiveandstablecatalystsinthiswork.

Inthiscontribution,wewillpresentasystematicvariationoftheCo:Mnratioin(Co,Mn)-N-Ccatalystswithandwithoutadditionalsulfurmodification.Sulfurcomesintoplayfortwomainreasons:(i)recently,weshowedthatsulfuradditionis beneficial to improve the number ofMeN4 sites that remain intact during the preparation2,3 and (ii) in case ofhydrogenevolutionearlyresultsbyTributsch4andlaterothersshowedthegoodperformanceofmetalsulfidesforHER.

Inthiswork,wewilldiscusstheimpactoftheaforementionedparametersonthehydrogenevolutionreactionwithastonishingstability.

Acknowledgement

FinancialSupportbytheGermanResearchFoundation(DFG)viatheExcellenceinitiativeTUDarmstadtGraduateSchoolofExcellenceEnergyScienceandEngineering(ESE)(GSC1070)isacknowledged.

References(1)Liang,H.-W.;Brüller,S.;Dong,R.;Zhang,J.;Feng,X.;Müllen,K.Naturecommunications2015,6,7992EP-.(2)Herrmann,I.;Kramm,U.I.;Radnik,J.;Fiechter,S.;Bogdanoff,P.J.Electrochem.Soc.2009,156,B1283-B1292.(3)Kramm,U.I.;Herrmann-Geppert,I.;Fiechter,S.;Zehl,G.;Zizak,I.;Dorbandt,I.;Schmeißer,D.;Bogdanoff,P.J.Mater.Chem.A2014,2,2663(4)Tributsch,H.;Bennett,J.C.Electroanalyticalchemsitryandinterfacialelectrochemistry1977,81,97–111.


47


Hydrogenreaching“fossilparity”aroundtheworld

BjørnSimonsen

[email protected]

Summary.

Withthefallingpricesofrenewableenergy,renewablehydrogenfromwaterelectrolysisisgraduallybecomingmoreandmorecompetitivewithbothliquidfossilfuelsandhydrogenfromsteam-methanereforming.WiththetechnologypresentlyavailablefromNelHydrogen,“fossilparity”isalreadyafactseveralplacesintheworld.

Abstract.

Renewableenergyisbeingexploitedatanincreasingscalearoundtheworld,bothduetoclimateandenvironmentalreasons,butalsoenergysecurity.Lately,renewableenergieshavealsobecomecostcompetitivewithfossilalternativesinmanyregionsacrosstheworld.Mostofthenew,renewablegenerationcapacitybeinginstalledissolarandwind,whichresultinhourly,dailyandseasonalchangesintheelectricityproduction.Thisleadstochallengesfortheelectricitygrid,sincetheelectricityconsumptionandproductionisgraduallybeingmoredecoupled.Forenergyproducersthisresultsinhighlyfluctuatingelectricityprices,andageneraltrendoffallingspotprices.

Inordertocaptureandstoreelectricityinperiodsofexcess,andcreateaddedvalue,energycompaniescanconvertthiselectricityintohigh-valuehydrogen,whichhasawiderangeofapplications,andcanprovideelectricityatalatertimeanddifferentplacethanwhenandwhereitwasproduced.

Largequantitiesofhydrogenisalreadyusedintheindustrialsectortoday,mainlyforammoniaproductionandinrefineries.Thesourceofthishydrogenisfromfromnaturalgas,oilandcoaltoday,andupuntilrecently,hydrogenproducedviaelectrolysishasnotbeenabletocompetewithfossilhydrogen,neitheronaCAPEX-basecomparedtosteammethanereformers,noronanOPEXbase,electricitycomparedtonaturalgas.However,withthepricesofrenewablefallingatasteadyrate,andlargescaleelectrolyserplants,basedonanewplantdesignbyNel,fossilparitywillalsobereachedwithintheindustrialsector.

NelHydrogenhasdevelopedhydrogenproductiontechnologybasedonwaterelectrolysissince1927,andbuiltseveralofthelargestelectrolysis-basedhydrogenproductionplantsinhistory.90yearsafterthestart,thetechnologyismorerelevantthanever,providingtheworldwithaflexibleandcleanenergycarrier,asimpleandeffectivewayofstoringenergy,increasingthevalueandamountofrenewableenergywhichcanbeimplementedintheenergysystem.

Renewablehydrogencanandwillbeproducedpracticallyallovertheworld,outcompetefossilliquidfuelsatthepump,andeventuallyalsohydrogengeneratedfromsteam-methanereformingfortheindustrysector,openingupaverylargeandexistingmarketforelectrolysis,whilereducingassociatedcarbonemissionsdrastically.


48


PERIC’sdevelopmentonAELandSPEtechnology

FENGDonghui1a;CHENTianshan1b;DINGRui1c;MAFei1d;XIEXiaofeng2a;aPurificationEquipmentResearchInstituteofCSIC,Handan,China

bTsinghuaUniversity,Beijing,China

[email protected]

Summary.Withtheresearchanddevelopmentonalkaline-typeelectrolyzerandSPEtechnologyformorethan50years,PERIChasbeensucceedinginbothlarge-scalehydrogengasgenerationwithpressurizationandlowpowerconsumptionfeatures.ThisisalsobeneficialtotheusersofPERIC’sproducts.

Abstract.BelongingtoChinaShipbuildingIndustryCorporation,PurificationEquipmentResearchInstituteofCSIC,China(Hereinafter calledasPERIC)was founded in1966. Since its establishment,PERIChas focusedon the researchanddevelopment,designandproduction,technicalservicesformilitaryandcivilianindustries.Uptonow,therehavebeenmorethan500differentkindsofproductswithhighreliabilityandadvancedtechnologytobesuccessfullysuppliedforbothdomesticandinternationalcustomersincivilianandmilitariesindustries.ThemaintechnologiesresearchedanddevelopedbyPERICarethefollowings:applicationchemistry,high-energychemistryengineering,H2-O2gasgenerationbywaterelectrolysis,hydrogeneliminationfornuclearpowerplant,gaspurificationandanalysis,electronicsspecial-typegas,catalyst,safetyguardsystem,etc.

As one of themost successful technologies and products, hydrogen generation technology and products bywaterelectrolysishasbeenworldwidemarketedandusedforallsortsofcivilianindustriessince1970s.Asofnow,theH2gascapacityrangesfrom0.5Nm3/hrto1000Nm3/hrfromasinglealkaline-typeelectrolyzerwithratedoperatingpressure1.50MPa(g),0.10Nm3/hrto10Nm3/hrfromasinglePEM-typeelectrolyzerwithratedoperatingpressure4.0MPa(g);thekeyfeaturesofthealkaline-typeelectrolyzeraretightlye-sealing,lowpowerconsumptionandlong-termoperatinglife,etc..

H2capacity:0.5Nm3/hr~1000Nm3/hr

Ratedpressure:1.50MPa(g);

Ratedtemperature:90Deg.C;

O2contentinH2:lessthan0.2%;

H2contentinO2:lessthan0.8%;

DCpowerconsum.:lessthan4.3kWh/Nm3H2AcornerofPERIC’sworkshop

Inordertosatisfythediverserequirements

fromdifferentcustomers,therehavebeen

fourkindsofhydrogengenerationsystem

asshowninthepictures.

PERICwillkeepitsstepsforwardcontinuously

onresearchanddevelopment,innovation

andimprovementonelectrolyzers,tosatisfy

themultipurposefromavarityofcustomers.

ElectrolyzerswithdifferentH2capacity


49

AbstractNo.27

AlkalineWaterElectrolyzersWithBaseMetalCatalystsShowing1A/cm2At1.75V

ByZengcaiLiu,SyedSajjad,YanGao,HongzhouYang,RichardIMasel

DioxideMaterials,3998FAUBlvd#300,BocaRaton,Fl,[email protected]

Summary.AlkalinewaterelectrolyzerswithbasemetalcatalystsandSustainion™membranesshow1A/cm2at1.75Vin1MKOHat80°C.

Abstract.

This paper will describe the performance of DioxideMaterials’ new Sustainion™ membranes in alkaline waterelectrolyzerswithbasemetalcatalysts.Figure1showstheconductivityofthemembranes.Noticethattheconductivityis a factor of 2-4 higher than the closest competitor. theconductivityisstableforthousandsofhoursat60°Cin1MKOH.

Dioxide Materials has done testing of the membranes inAlkalinewaterelectrolyzers.Figure2showsarunat60°Cin1MKOHusingcommercialnanoparticlesfromSigmaAldrichascatalysts.Weobservestableperformancefor1000hourwithaaveragevoltagelossofonly10µV/hr.

Figure3showsashortrundonewithanoptimizedcatalyst.Thiscatalystshows1A/cm2at1.75V.

Figure2ThestabilityofanelectrolyzerwithNiFeO4anodecatalystsandNiFeCocathodecatalystsat60°C and 1 M KOH. In this case, the current wasmaintainedat1A/cm²andthevoltagetomaintainthecurrentwasmeasuredasafunctionoftime

Figure3Ashortrunwithanimprovedcatalystat80°Cand 1 M KOH. In this case, the current wasmaintainedat1A/cm²andthevoltagetomaintainthecurrentwasmeasuredasafunctionoftime

Figure 1 The measured conductivity of DioxideMaterials’Sustainion™membranesin1MKOH


50

AbstractNo.28

AuniqueapproachforhighintensityalkalinewaterelectrolysisusingamembranelessDivergent-Electrode-Flow-Through(DEFTTM)electrolyser

MIGillespiea,RJKriekbaDemcoTECHEngineeringonbehalfofHydroxHoldingsLtd.,Modderfontein,Johannesburg,1645,SouthAfrica

bElectrochemistryforEnergy&EnvironmentGroup(EEE),ResearchFocusArea:ChemicalResourceBeneficiation(CRB),North-WestUniversity,PrivateBagX6001,Potchefstroom,2520,SouthAfrica

[email protected]

Summary.Amembranelessalkalinewaterelectrolysistechnology,thatmanipulatestheflowofelectrolyteinopposingdirections,whichachieves(i)separationoftheconstituentgases,(ii)simplificationoftheelectrolyserdesign,and(iii)eliminationofkeylimitationsofconventionalalkalinewaterelectrolysers,e.g.lowcurrentdensities.

Abstract.Alkalinewaterelectrolysersarehinderedbycross-diffusionofgasesacrossthemembrane/diaphragm,limitedcurrentdensitiesandlowoperatingpressures.Itremainsawelldevelopedtechnologywithanumberofadvantagesextendingtoanenvironmentthatallowstheuseofinexpensivematerialsofconstruction,however,itremainscapitalintensiveduetolowoperatingcurrentdensities[1].ProtonExchangeMembrane(PEM)electrolysersovercomesomeof the weaknesses associated with alkaline systems by allowing efficient performance at high current densities,pressurisedoperationandproductionofsuperiorgaspurities.Theaggressiveacidicregime,however,requirestheuseofdistinctconstructionmaterialsthatarescarceandexpensive[1].

TheDivergent-Electrode-Flow-Through(DEFTTM)solutioncapturessomekeyadvantagesfrombothalkalineandPEMsystems (Figure 1).Uninterrupted flowof an alkaline electrolyte flows through two close proximity circular porouselectrodes,oflimiteddiameter(~30mm)andelectrodegap(>2mm),thereforeeliminatingtheneedforamembrane.Forthisconfigurationflowistheonlyrequirementforcontinuoushighpuritygasseparation(98.98vol%H2and97.60vol%O2ata flowvelocityof0.075m.s-1).This isareliableandsimpleapproachcapableofachievingstablecurrentdensitiesashighas3.5A.cm-2at reasonablecellpotentialsemployingoptimalcatalysts [2].Thecurrent focus isonscalingtheDEFTTMtechnologytosuccessfullyproduceelevatedquantitiesofhydrogengas.

References.

[1] M.Carmo,D.L.Fritz, J.Mergel,andD.Stolten,“AcomprehensivereviewonPEMwaterelectrolysis,” Int. J.HydrogenEnergy,vol.38,no.12,pp.4901–4934,2013.

[2] M. I. Gillespie, F. van der Merwe, and R. J. Kriek, “Performance evaluation of a membraneless divergentelectrode-flow-through (DEFT) alkalineelectrolyserbasedonoptimisationof electrolytic flowandelectrodegap,”J.PowerSources,vol.293,pp.228–235,2015.

Figure3:OperatingprincipleofapolepairofelectrodesfromamembranelessDEFTTMelectrolyserstack


51

AbstractNo.29

Hightemperaturealkalineelectrolysis

ChristodoulosChatzichristodoulouaandMogensBjergMogensenaaTechnicalUniversityofDenmark,DepartmentofEnergyConversionandStorage,Frederiksborgvej399,4000

[email protected]

Summary.Hightemperatureandpressurealkalineelectrolysiscellshavebeendemonstratedatcurrentdensitiesofupto3.75Acm-2atacellvoltageof1.75Vat200°Cand20bar,correspondingtoanelectricalefficiencyof85%,withrelativelystableperformanceover400h,therebypromisingadrasticcostreductioninelectrolyticH2production.

Abstract.Alkalineelectrolysisisaproventechnologywithseverallargescalefacilitiesforhydrogenproductionrealizedandoperated reliably fordecades.Nevertheless, its broaderdeployment is hinderedby the relativelyhigh cost forhydrogenproduction.Toovercomethisobstacle,itisnecessarytoimprovecellefficiency,increasetheproductionrate,and decrease capital cost. Since conventional alkaline electrolysis technology has reached maturation, only smallincrementalimprovementscanbeexpected.Toachieveadrasticstepforward,wehavedevelopedanewgenerationofalkalineelectrolysiscellsthatcanoperateatelevatedtemperatureandpressure,producingpressurizedhydrogenathighrateandhighelectricalefficiency.

Theconcept relieson thedevelopmentof corrosion resistanthigh temperaturediaphragms,basedonmesoporousceramicmembraneswhereaqueousKOHisimmobilizedbycapillaryforces,incombinationwithgasdiffusionelectrodesthatovercomemasstransportlimitationsatlargeproductionrates.Raisingtheoperatingtemperatureoffersameansto drastically improve performance, as both ionic transport and reaction kinetics are exponentially activated withtemperature.Indeed,wehavedemonstratedalkalineelectrolysiscellsoperatingat200-250°Cand20-50baratveryhigh efficiencies and power densities. This enables high production rates near the thermoneutral voltage, therebyovercomingtheneedforcooling.

Thisworkwillprovideanoverviewoftheexploratorytechnicalstudiesundertakensofar.Threeelectrochemicalteststationshavebeenestablishedtocarryourexperimentsatelevatedpressures(upto99bar)andtemperatures(upto300 °C). The conductivity of aqueous KOH was investigated at elevated temperatures to establish the optimumconcentrationat200-250°C.Anoptimumvalueof0.84Scm-1wasestablishedat200°C for45wt%aqueousKOHimmobilizedinmesoporousSrTiO3.Gasdiffusionelectrodesweredevelopedusingmetalfoamsloadedwithdifferentnon-preciousmetalelectrocatalysts inordertoreducetheoverpotentials foroxygenandhydrogenevolution.Smallcellshavebeenfabricatedandoperatedatcurrentdensitiesofupto1.75Acm-2and3.75Acm-2atcellvoltagesof1.5Vand1.75Vat200°Cat20bar,correspondingtoelectricalefficienciesofalmost99%and85%,respectively.Long-termoperationat200°Cwassuccessfullydemonstratedfor400h,suggestingrelativelystablecellperformance.Finally,low-costproductionmethodshavebeenutilizedforafirstscale-upofthecellsizefrom1cm2to25cm2.Effortsarecurrentlydirectedtowardstheinvestigationoftheintrinsicactivityofmixedoxidesfortheoxygenevolutionreactionatelevatedtemperaturesandpressures,andtowardsthedevelopmentofhighsurfaceareaelectrodesfortestingoffullcellsat25cm2size.


52


Tailoringelectrodeinterfacesforconversion

JohnTSIrvine

[email protected]

Summary.Theelectrochemicalreactionsinfuelcellsandelectrolysersoccurattheinterfacebetweenelectrodesandelectrolyte. Herewe look at attempts to nanoengineer this interface to enhanceperformance and also probe thechangesinlocalstructurethatrelatetoactivationorageingduringoperation.

Abstract.Thedevelopmentofnewandrenewablesourcesofenergyisessentialtomeetglobalenergyneedsandtoreducetheemissionsofpollutantsthatcontributetothereductionofairqualityandtonetgreenhousegasproduction.Theintermittencyofrenewableelectricityproducedfrominparticularwind,isamajorbarriertofurtherexpansionandcanresultinsignificantperiodswhengridbalancingisrequiredtomaintainintegrityofsupply.

Hightemperaturesteamelectrolysis(HTSE)isahighlyefficientprocessforhydrogenproductionandiscarbon-neutralprovidedthattheelectricitycomesfromarenewablesource1.Electricityandheatarecombinedwithinasolidoxideelectrolysiscell(SOEC)fortheelectrochemicalreductionofsteamtohydrogenplusoxideionsatthehydrogenelectrode(cathode),followedbyoxideionmigrationacrossasolidelectrolytetotheoxygenelectrode(anode)whereoxygenisevolved.Recentinterestinsteamelectrolysishasbeenlargelyconcernedwithperformance,stabilityanddegradationissuesrelatingtohighlydevelopedSOFCmaterials2.ThesehaveformedastartingpointforSOECdevelopment;howeverrecent work on exsolution SOEC cathodes has yielded enhanced performances in robust systems3. Besides steamelectrolysis,CO2electrolysisusingSOECshasalsoattractedincreasingresearcheffortsworldwideduetotheemissionofgreenhousegasesintotheatmosphereandtheresultingclimatechange4.AkeyadvantageofbothsteamandCO2high temperature electrolysis processes is that electrical energy demand significantly decreases as temperatureincreases,withthermalenergyprovidingtheadditionalenergyfortheprocess.ThiscanbeprovidedbyJouleheatingcapitalising on ohmic losses in the SOEC stacks. Autothermal operation, where ohmic losses and entropic energydemandsmatchisoftenconsideredasanappropriatemodeofoperation.

HerewepresentthegrowthofafinelydispersedarrayofanchoredmetalnanoparticlesonanoxideelectrodethroughelectrochemicalpolingofaSOCat2Vfora fewseconds,yieldingasevenfold increase in fuelcellmaximumpowerdensity.Thesenewelectrodestructuresarecapableofdeliveringhighperformancesinbothfuelcellandelectrolysismode(e.g.2Wcm-2inhumidifiedH2and2.75Acm

-2at1.3Vin50%H2O/N2,at900°C).Boththenanostructuresandcorrespondingelectrochemicalactivityshownodegradationover150hoursoftesting.Theseresultsnotonlyprovethatinoperando treatments canyieldemergentnanomaterials,which in turndeliverexceptionalperformance,butalsoprovideproofofconceptthatelectrolysisandfuelcellscanbeunifiedinasingle,highperformance,versatileandeasilymanufacturabledevice.Thisopensexcitingnewpossibilitiesforsimple,quasi-instantaneousproductionofhighlyactivenanostructuresforreinvigoratingSOCcellsduringoperation

1A.Hauch,S.D.Ebbesen,S.H.JensenandM.Mogensen,J.Mater.Chem.,18(20),2331(2008).2A.Brisse,J.SchefoldandM.Zahid,Int.J.HydrogenEnergy,33(20),5375(2008).3J-H.Myung,D.Neagu,D.N..Miller&J.T.S.Irvine,Nature,2016,doi:10.1038/nature190904S.D.Ebbesen,M.Mogensen,J.PowerSources,193(1),349(2009)


53

AbstractNo.31

DegradationBehaviorof(La,Sr)(Fe,Co)O3SolidOxideCellOxygenElectrodesDuringReversibleElectrolysisandFuelCellOperation

JustinRailsbacka,HongqianWanga,MatthewYLua,andScottABarnettaaDepartmentofMaterialsScience&Engineering,NorthwesternUniversity,Evanston,ILUSA

[email protected]

Summary.Mostpriorstudiesofoxygenelectrodedegradationduringelectrolysishavefocusedon(La,Sr)MnO3(LSM)–less is known about (La,Sr)(Fe,Co)O3 (LSCF). Here we report results showing that LSCF degrades by a differentmechanismthanLSM,duetoaloweroverpotentialundertypicaloperatingconditions.

Abstract.Previouswork on reversible solid oxide electrolysis has focused on LSM-YSZ oxygen electrodes,1-3 wheredegradationattheelectrode-electrolyteinterfaceleadingtocrackinganddelaminationhasbeenobserved.Asimilarmechanism is observed during DC electrolysis, although degradation is more rapid than in current switching.2Degradation rates≲1%/khrhavebeen reportedduring reversingcurrentoperation forLSM-YSZ,1butonly for lowcurrentdensities/overpotentials1orforcurrentswitchingwithverylowelectrolysisdutyfractions.4Thus,itisimportanttodeterminewhetherotheroxygenelectrodematerialscanprovidelowdegradationratesatahighercurrentdensityjthaninLSM-YSZ.Furthermore,energystorageinvolvingco-electrolysisispredictedtobesubstantiallymoreefficientandeconomicaliftheSOCoperatesatloweroperatingtemperatures,5solowtemperatureelectrodesareofparticularinterest.

HerewepresentlifetestsonsymmetricLSCF/GDC/LSCFcellsoperatingundercurrentswitching,showingtheeffectofvaried j andoverpotentialsh ondegradation. This is the first detailed studyof LSCFelectrodedegradationduringcurrent switching, to our knowledge. Symmetric cells have the advantage of isolating degradation of the oxygenelectrode,withouttheneedtodeconvolutefromafuelelectrode.Thesecellsallowfocustobeplacedondegradationin the LSCF and at the LSCF/GDC interface; since there is no YSZ electrolyte, there are no LSCF-YSZ reactions.Microstructuralevaluationispresentedandcomparedwiththeelectrochemicaldegradationinordertoobservethenatureofthedegradationmechanisms.

CurrentswitchinglifetestsofLSCFonGDCsymmetriccellswereperformedinambientairat700oCforabout1000hat0.7,0.9,1.0,and1.5A/cm2.Thecellresistancedegradationrateincreasedwithincreasingj.MostoftheresistanceincreasewasattributedtotheelectrodepolarizationresistanceRP.Thecelloperatedat0.7A/cm

2hadarelativelyslowdegradationrateof0.6±0.4%/kh.Ontheotherhand,at1.5A/cm2thedegradationwasveryrapidoverthefirst~500h,increasingRPby0.1Wcm

2,butleveledoffduringtheremaining500h.Alldegradationoccurredatη£0.1V,belowthevaluepredictedtocauseGDCelectrolytedelaminationduetooxygenbubbleformation,andindeedtherewerenosignificantchangesobservedintheelectrolytemicrostructureortheohmicresistance.3DtomographyusingFIB-SEMwasperformedoncellsafterlifetestingatj=0,0.7,and1.5A/cm2showingthattheLSCFstructurecoarsenedatthehighestjvalues.However,themicrostructuralchangesdidnotappearsufficienttoexplaintheobservedRPincrease,basedonAdler-Lane-Steele(ALS)modelcalculations.Itissuggestedthathighjoperationmightalsocausedegradationbyacceleratingcationtransportintheelectrode,e.g.Srsurfacesegregation.TheALSmodelcalculationsindicatethatadecreaseinoxygensurfaceexchangeratebyafactorof~4,similartothatobservedpreviouslyduetoSrsegregation,6accountsformostofthedegradation.ResultsonSrsegregationwillbereported.

1. G.A.Hughes,J.G.Railsback,K.J.Yakal-Kremski,D.M.ButtsandS.A.Barnett,FaradayDiscuss,182,365(2015).2. G.A.Hughes,K.Yakal-KremskiandS.A.Barnett,PhysChemChemPhys,15,17257(2013).3. G.A.Hughes,K.Yakal-Kremski,A.V.CallandS.A.Barnett,JElectrochemSoc,159,F858(2012).4. C.Graves,S.D.Ebbesen,S.H.Jensen,S.B.SimonsenandM.B.Mogensen,Naturematerials,14,239(2015).5. S.H.Jensen,C.Graves,M.Mogensen,C.Wendel,R.Braun,G.Hughes,Z.GaoandS.A.Barnett,EnergEnvironSci,

8,2471(2015).6. H.Wang,K.J.Yakal-Kremski,T.Yeh,G.M.Rupp,A.Limbeck,J.FleigandS.A.Barnett,JElectrochemSoc,163,F581

(2016).


54

AbstractNo.32

Eliminatingdegradationandrepairingdamageinsolidoxidecellandstackfuelelectrodes

TheisL.Skaftea,b,JohanHjelmb,PeterBlennowa,andChristopherGravesbaHaldorTopsoeA/S,HaldorTopsøesAllé1,2800Kgs.Lyngby,Denmark

bDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,Risøcampus,Frederiksborgvej399,4000Roskilde,Denmark

[email protected]

Summary.The fuel electrodeof commercial solid oxide electrolysis cells and stacks are shown to be repairable byemployingwetinfiltrationinanovelmanner.Performancepriortootherwisefataldamagewasentirelyregainedandlong-termdegradationoverthecourseofthousandsofhoursiseliminated.

Abstract.Thesolidoxidecell(SOC)couldplayavitalroleinenergystoragewhentheshareofintermittentelectricityproductionishigh.However,thewide-scalecommercializationofthetechnologyisstillhinderedbylimitedlifetime.Here, we address this issue by examining the potential for repairing various failure and degradation mechanismsoccurringinthefuelelectrode,therebyextendingthepotentiallifetimeofaSOCsystem.Wesuccessfullyinfiltratedthenickel and yttria-stabilized zirconia cermet (Ni-YSZ) electrode in commercial cells with Gd-doped ceria (CGO) afteroperation.Bythismethodwefullyrepairedthefuelelectrodeaftersimulatedreactantstarvation,carbonformationand thousands of hours of steady degradation. The potential for entirely eliminating the degradation of the fuelelectrode was proven by infiltrating after microstructural stabilization had occurred. Moreover, we demonstratedscalabilityoftheconceptbyrepairingan8-cellstackbasedonacommercialdesign.

Figure4|Illustrationofonesuggesteddegradationmechanismandhowinfiltrationrepairsthedamage.a,electronssuppliedbytheNiparticle,oxygenionssuppliedbytheYSZparticleandgasmeetsinthereactionzoneatthetriple-phase-boundary(3PB).b,as

localdelaminationtakesplace,thereactionzonemovesandthe3PBshrinks.Forparticleswithpoorconnection,completedelaminationcanoccur.c,thedelaminationisfilledbyinfiltratednanoparticlesandthereactionzoneisextended.


55

AbstractNo.33

Post-testanalysisofasolidoxideelectrolysiscelloperatedfor23000h

QingxiFua,MarJuez-Lorenzob,JosefSchefolda,AnnabelleBrisseaaEuropeanInstituteforEnergyResearch(EIFER),Emmy-Noether-Strasse11,76131Karlsruhe,Germany

bFraunhoferInstituteforChemicalTechnologyICT,Joseph-von-Fraunhofer-Strasse7,76327Pfinztal,[email protected]

Summary.Thepresentworkpresentsthemicrostructuralandcompositionalchangeofanelectrolytesupportedsolidoxidecelloperatedinthesteam-electrolysismodeforadurationofmorethan23000hwithacurrentdensityofupto-0.9Acm-2.

Abstract.Anelectrolytesupportedsolidoxidecellwithanactiveareaof45cm2wasoperatedinthesteam-electrolysismodeforadurationofmorethan23000h,ofwhich20000hwithacurrentdensityof j=-0.9Acm-2andasteamconversionof51%.Thecelliscomposedofascandia/ceria-stabilizedzirconia(6Sc1CeSZ)electrolyteofabout130µmthickness, gadolinia-substituted ceria (CGO) diffusion-barrier/adhesion layers between electrolyte and electrodes, alanthanum strontium cobalt ferrite (LSCF) oxygen electrode, and a Ni/CGO steam/hydrogen electrode. In thegalvanostaticoperationperiodwithj=-0.9Acm-2,thecellvoltageincreasedatarateof7.4mV/1000h(0.6%/1000h).In-situelectrochemicalimpedancespectroscopyrevealedthatthecelldegradationwasdominatedbytheincreasingohmicresistance,whichcanbeattributedmainlytothedecayoftheionicconductivityoftheelectrolyte.Inaddition,asmallincreaseofthepolarizationresistancecausedbyanincreasinglossfromtheinterfacialchargetransferprocesswasidentified[1].

Exceptthedelaminationofasmallfractionoftheoxygenelectrode,thecellshowednomechanicaldamageafterbeingdismountedfromthetestrig.Inordertounderstandbetterthedegradationmechanism,post-testanalysisofthecellhasbeenconductedusingscanningelectronmicroscopy(SEM)andenergy-dispersiveX-rayspectroscopy(EDX).Atthesteam/hydrogenelectrode, Si-accumulationwasobserved at the interfacebetween theNi/CGO layer and theCGOadhesionlayer(Figure1).TheamountofSidecreasesfromthecentretotheouteredgeofthecell.ItisspeculatedthatSioriginatingfromthewatersupplysystemiscarriedbythesteam/hydrogenstreamtothecellanddepositsthenattheproximityofreactionsites.Si-accumulationcouldcontributetotheobservedincreaseofbothohmicandcharge-transfer resistances.At theoxygenelectrode, formationof SrZrO3 at theCGO/6Sc1CeSZ interface as a result of Sr-migrationfromtheLSCFelectrodethroughtheCGOdiffusion-barrierlayerwasobserved,whichshouldalsoleadtoanincreasingohmicresistanceof thecell.Atthesurfaceof theoxygenelectrode,a foreignphaserich inPandSrwasidentified,whichcanbecorrelatedtotheobservedsurfacedarkening,causedmostprobablybytheimpuritiesinthecompressorairusedasthepurgegasattheoxygenelectrode.

Figure1:Elementalmappingofthesteam/hydrogenelectrode,showingaccumulationofSi.

[1]J.Schefold,A.Brisse,H.Poepke,Int.J.HydrogenEnergy,2017,inpress


56

AbstractNo.34

Regeneratingtheperformanceofsolidoxideelectrolyzersbyperiodictreatmentstoextendlifetime

ChristopherGravesa,TheisL.Skaftea,b,MarcoMarchesea,c,AnneHaucha,AndreaLanzinic,KarinVelsHansena,TorbenJacobsena,MingChena,PeterBlennowb,JohanHjelma

aTechnicalUniversityofDenmark,DepartmentofEnergyConversionandStorage,4000Roskilde,DenmarkbHaldorTopsoeA/S,HaldorTopsøesAllé1,2800Kgs.Lyngby,Denmark

cDepartmentofEnergy,PolitecnicodiTorino,Turin,[email protected]

Summary.Solidoxideelectrolyzerscanproducefuelsusingrenewableelectricitywithhigherenergyefficiencythanothertypesofelectrolyzers,buttheyareknowntosufferfromshorteroperatinglifetimes.Wepresentseveralwaysthatdevicelifetimecanbeextendedbyapplyingperiodictreatmentstoregeneratetheperformance.

Abstract.Duetotheirhightemperatureoperation,solidoxideelectrolyzers(SOEs)areabletosplitH2OintoH2andO2,andCO2intoCOandO2,orevenbothH2OandCO2directlyintoCH4andO2,withnearly100%energyefficiency.Thismakesthetechnologyofgreatinterestforlarge-scalerenewableelectricitystorageandtransportationfuelproduction.However, thedemonstratedSOEoperating lifetime is shorter than thatof commercial alkalineelectrolyzers,whichresultsinahighercapitalcost.OngoingR&Dincellandstackdesignshasyieldedconsiderableimprovementsinlifetimeforsteady-stateelectrolysisoperation.

Wehave been investigating new, alternativeways to extend lifetimeby periodically subjecting the cell or stack totreatmentsthatrestoreperformance.Theseincludeexsitutreatments–wherethedeviceiscooleddown,repaired,andheatedbackuptoresumeoperation–and insitutreatments–wheretheappliedvoltageorgascompositionisbrieflyadjustedtoinduceaboostinperformance.Wehavedemonstratedexsiturepairbyinfiltrationofcellsandastackwithprecursorsolutionsthatproduceelectrocatalystnanoparticlesinthenickel-basedfuelelectrode,whichwasthesourceofperformancedegradationduringthousandsofhoursofoperation,andfoundthatperformancecouldberegainedtotheinitiallevel.Oneinsitutreatmentistheexposureofcertainfuel-electrodestooxidizinggassesandthenback to fuel gasses, which results in restoration of nano-structured electrode surface features that were lost bycoarseningprocesses.Anotheristheapplicationofshortcontrolledpulsesofhighcathodicpolarization,whichwefoundcansimilarlyproducenano-structuredinterfacesthatimproveelectrodeperformance.

The presentation will also summarize our current knowledge of the mechanisms by which these regenerationtreatmentswork,limitationsofthetreatments,thetimeperiodsforhowlongthere-activationlastsuntilthetreatmentmustbeusedagain,andsomeexamplesfromliteraturethatarerelevanttothisnewstrategyforlifetimeextension.

Resis

tance

Time

Regenerationtreatment


57


MegawattscaledualstackPEMelectrolysisdevelopmentforenhancingrenewableenergyintegrationbyprovidinggridservicesduringhydrogengeneration

JanVaes,DenisThomas

HydrogenicsEuropeNV,nijverheidstraat48c,B-2260Oevel,[email protected]

Summary. Hydrogenics has developed an outdoor electrolyser that is able to convert 2.5 MW peak power intohydrogen.Theunitwasconceivedwithadual stack set-up, inorder toachieveahighoperational flexibilityand tominimizetotalcostofownershipfortheprojectowner.TheunitwillbeinstalledinHobro,Denmark,andwillbefullyoperationalin2017.Thesiteownerisaimingatgeneratingadditionalrevenuesbyofferingoperationalflexibilitytotheelectricitygrid.

Abstract. Hydrogen has a long standing history as a feedstock gas or process medium in industrial applications.Electrolytichydrogengenerationisagoodoptionwheneversmalltomediumflowsarerequired,andisalsooftenthetechnologyofchoicewhenhighpuritystreamsareneeded.Currentlythereisanincreaseddemandforelectrochemicalhydrogenbecauseitgivesananswertothegrowingpracticalissuesrelatedtotheintegrationofrenewableenergiesintoday’senergymix. In thepower-to-gasconcept, thatprovidesarealistic route foracarbon-freeeconomic future,waterelectrolysisisthekeytechnologytostorerenewableenergysurpluses,allowingthecrossoverbetweendifferentenergyvectors;electricityonthegrid,naturalgasaschemicalenergystorageandfuelfortransportapplications.

This contribution presents the PEM based electrolyser development in the Hybalance project. This FCH-JU andEnergynet.dk co-funded project illustrates how PEM water electrolysis, complimented with additional hydrogencompressionandtransportationtechnologies,demonstratesdifferenthydrogenapplicationsinreallifewhenanumberof important boundary conditions are met. The consortium partners in the project are Air Liquide, Neas energy,HydrogenValleyandtheCopenhagenHydrogenNetwork(CHN).

In the Hybalance project, electricity in converted by pressurized water electrolysis into hydrogen and furthercompressedandtransportedathighpressureforHydrogendeliverytothefuelingstationsoperatedbyCHNinDenmark.The500kgperdayproductionunit isbasedonHydrogenics1500cm²PEMplatformand is anext iterationof thepreviouslydemonstratedsinglestackunits.Duringthisdevelopmentanumberofchallengeshavebeentackled.TheFCH-JUefficiencytargetwasputforwardasadesigncriterionandinadditionthecommercialoperationoftheplantforaminimumoffifteenyearsrequiredaveryreliable,availableinstallationwithlowdegradationrateoftheefficiency.With these conditionsdefining theprocesswindow in termsof stack currentdensity,operational temperatureandredundantcomponents,additionalconstraintsintermsofharmonicdistortionontheelectricalgridandnoiseemissionin a residential area had to bemet. Finally, special attention had to be given to the operational flexibility of theelectrolyser,allowingforademandside(hydrogen)orsupplyside(excessofcheapelectricity)controlofthehydrogenproductionrate,inordertoachievethelowestcostofownershipfortheentireplant.


58

AbstractNo.36

IncreasingPEMwaterelectrolysisenergeticefficiencybyasurfacemodificationofTigasdiffusionlayer

TomasBystron1a,MartinVesely2a,MartinPaidar3aandKarelBouzek4aaUniversityofChemistryandTechnologyPrague,Technicka5,Prague6,16628,CzechRepublic

[email protected]

Summary.AstateofartgasdiffusionlayerforPEMwaterelectrolysisanodeisusuallybasedonporousTi.However,tooextensivepassivationlayerofTiincreasessurfacecontactresistanceandconsequentlyenergeticlosses.AppropriatesurfacemodificationofTileadstoimprovedandstableperformanceofwaterelectrolyser.

Abstract. Proton exchangemembrane (PEM) water electrolysis attracts a lot of attention as an important part ofHydrogenEconomyConcept.Whiletheprocesscanbeoperatedwithhighefficiency,space-timeyieldandflexibility,there are several issues limiting severely its practical applicability on a larger scale. Themost important ones areconnectedwithstabilityofmaterialsontheanodepartofthecellwherehighelectrodepotentialiscombinedwithlowpH.Suchconditionsaredetrimentalformajorityofelectron-conductingmaterials.Forexample,onlyTiorTacanbeefficientlyusedforagasdiffusionlayerconstruction.Whilethermodynamicallyhighlyunstableunderthementionedconditions,theirstableandintactpassivationlayerefficientlyprotectsbulkofthemetalfromfurtherdissolution.Ontheother hand, presenceof thepassivation layer increases surface contact resistance and consequently decreasesenergeticefficiencyoftheelectrolysisprocessespeciallywhenoperatedathighintensity.Common,thoughnotoftenmentionedsolutioniscoatingofthegasdiffusionlayerwithmetalslikePt.This,however,furtherincreasesalreadyhighinvestmentcostofthewholeprocess.

InthisstudyanattemptisreportedtounderstandmoredeeplyprocessesoccurringontheTisurfaceduringpolarisationundertheconditionsrelevanttothePEMwaterelectrolysis.OnthebaseoftheknowledgeobtainedanattemptwasmadetosolvetheissueandtodecreasethesurfacecontactresistancebyappropriatesurfacemodificationoftheTigasdiffusionlayer.ApromisingapproachrepresentedetchingoftheTiinanappropriateacidsolution.Itlednotonlytoalargereductionofenergylossesduringwaterelectrolysisrelatedtothecontactresistancebutalsotoadecreaseofperformancedegradationrate.Theobservedeffectwas,inmoredetails,studiedusingtechniquessuchasSecondaryIonMassSpectrometry,X-rayphotoelectronspectroscopyorclassicalelectrochemicalmethods.Inthepresentation,theresultswillbediscussedincontextofthe(sub)surfacelayercompositionandpassivationlayerthicknessrelatedtotheanodeperformanceanddegradationrate.

Acknowledgement

Financial support of this study by the Grant Agency of the Czech Republic with the framework of the project No.15-02407Jisgratefullyacknowledged.


59

AbstractNo.37

MaterialsandcoatingsforPEMwaterelectrolysers

AlejandroOyarcea,SigridLædrea,SidselMeliHanethoa,LuciaMendizabalbandAndersØdegårda

a SINTEF Materials and Chemistry, Trondheim, Norway b Department of Surface Physics and Technology, IK4-TEKNIKER,Spain

[email protected],+47-93003263Summary.PEMelectrolyzerscoupledwithrenewableenergysources(windandsolar)representoneofthemostpromisingcandidatesforcleanhydrogenproduction.Bipolarplates(BPP)couldbeexposedtoacidicenvironment,butalsomustwithstandhighovervoltage(upto2V)intheanodicsideofaPEMeletrolyzer.ThesefactorsstronglyreducethematerialcandidatesforBPPfabrication.Titanium(Ti)isconsideredasthestate-of-the-artmaterial.Ontheotherhand,Titendstoformaninsulatingpassiveoxidelayerthatincreasesinterfacialcontactresistance(ICR)anddiminisheselectrolyzercellefficiencyaselectrolyzerages.Therefore,electrolyzermanufacturersusuallyapplyexpensiveconductivecoatings.Abstract.

Inthisstudy,anextensivecharacterizationofapromisingnovelcoatingforBPPprotectiondepositedonTiispresented.Thecoating(Ta_ITO)ismadeofatantalumlayer(Ta)actingasananti-corrosionbarrierfollowedbyathinindiumtinoxide(ITO)conductivefilm.TalayerwasdepositedbyHighPowerPulsedMagnetronSputteringTechnology(HPPMS)thatproducesdenseandlow-defectmicrostructurefilms.SeveralITOlayers

depositedbypulsedDCmagnetronsputtering(PMS)wereinvestigatedbothex-situandin-situ.ThecorrosionresistanceofdifferentTa_ITOcoatingswasinvestigatedusingpotentiostaticandpotentiodynamicmeasurementsinsimulatedPEMelectrolyzeranodicenvironment.Theeffectofthesubstratewasalsoanalysed.Thesampleswereimmersedina0.1MNa2SO4solutionthathadbeenpHadjustedbyadditionof1mMH2SO4.Temperature,potentialandlengthofthepotentiostaticpolarizationwerevaried,tostudytheeffectthiswouldhaveonboththesubstratesandtheTa_ITOcoatings.Beforeandaftereachpolarization,theICRwasmeasuredinasetupsimilartotheonedescribedbyLædreetal.[1],withtheplatetobetestedplacedwithaGDLontopbetweentwogoldcoatedcopperplates(softcontactICR).In addition, porous titanium transport layers, PTLs, (or sinters) fromBEKAERTwere also coatedwith themost promising coatings. TheseweretestedasbothanodeandcathodePTLsinanelectrolyzerusingcommerciallyavailableMEAsandelectrolyzerhardware.Polarization

curves,EISandICRmeasurementswereperformedbeforeandafteranASTprotocoldevelopedin-houseandtheresultswerecomparedagainstuncoatedTi,aswellasnoblemetalcoatedTiPTLs.[1]Lædre,S.,etal.,TheeffectofpHandhalidesonthecorrosionprocessofstainlesssteelbipolarplatesforprotonexchangemembranefuelcells.InternationalJournalofHydrogenEnergy,2012.37(23):p.18537-18546.


60

AbstractNo.38

Flowfielddesignforhigh-pressurePEMelectrolysiscells

AndersChristianOlesenandSørenKnudsenKær

DepartmentofEnergyTechnology,AalborgUniversity,Pontoppidanstræde111,[email protected]

Summary.Tostudytheelectrochemicalbehaviouroffull-scale,flowfielddesignsofhigh-pressurePEMelectrolysiscells,acomputationalfluiddynamicsmodelhasbeendeveloped.Forasetofspecificoperatingconditions,differentflowfieldsareinvestigatedintermsoftheirabilitytohandlegasandheatmanagement.

Abstract. With the increasing interest in producing hydrogen through water electrolysis, the importance ofunderstandingthetransportphenomenagoverningitsoperationincreases.ToensureoptimaloperatingconditionsforPEMelectrolysis,itisparticularlyimportanttounderstandhowtheliquidfeed-waterdistributes.Waternotonlyservesareactant,italsoaidsincoolingduetoitshighspecificheatcapacity.Themovementofliquidwaterattheanodeisdifficulttomodel,sinceitishighlycoupledtotheformationofgasbubbles.Tocapturethecomplextwo-phaseflowbehaviourthattakesplacewithinmicro-channelsandporousmedia,ourresearchgrouphasdevelopedanEuler-EulermodelinthecomputationalfluiddynamicsmodellingframeworkofANSYSCFX.Inadditiontotwo-phaseflow,themodelaccountsforturbulence,speciestransportinthegasphase,heattransportinallthreephases(i.e.solid,gasandliquid),aswell as charge transportof electrons and ions.Our recent improvementshave focusedon themodels ability toaccountforphasechangeandelectrochemistryaswellasthemodellingoftwo-phaseflowregimes.

For comparison, an interdigitated andparallel channel flow fieldwill be investigatedwith regard to howwell theydistributegasandheat.Toobtainahighdurabilitywhenoperatingathighcurrentdensities,itisessentialthatliquidwater and temperature is evenlydistributionover theentire active surfacearea. In Figure1, a contourplotof thetemperaturedistributionwithinaninterdigitatedflowfieldispresentedasanexample.Theaxis-symmetricsimulationshowsthattheformationofhotspotsintheorderof8Cabovetheinlettemperaturecanoccurforacurrentdensityof3A/cm2andawaterstoichiometryof350.Thesespotsareprimarilylocatedunderneaththeoutletchannels.Toavoidthem,anin-depthdesignandsimulationstudyisnecessary.

Figure5:Contourplotofthetemperaturedistributionforaninterdigitatedflowfieldatacurrentdensityof3A/cm2andawater

stoichiometryof350.


61

AbstractNo.39

Protectivecoatingsforlow-costbipolarplatesandcurrentcollectorsofprotonexchangemembraneelectrolyzers

PhilippLettenmeiera,AsifS.Ansara,AldoS.GagoaandK.AndreasFriedricha

aInstituteofEngineeringThermodynamics,GermanAerospaceCenter,Pfaffenwaldring38-40,70569Stuttgart,Germany

[email protected]

Summary.

Vacuumplasmaspraying,aversatileapplicabletechnologytoapplyvarioustypesofcoatingstoawiderangeofsurfaces,isused toproducehighly stableandmultifunctional coatings for costeffective interconnectorsofprotonexchangemembrane(PEM)electrolyzers.

Abstract.

Hydrogen produced by PEM electrolysis technology is a promising solution for energy storage, integration ofrenewables,andpowergridstabilizationforacross-sectorialgreenenergychain.ThemostexpensivecomponentsofthePEMelectrolyzerstackarethebipolarplates(BPP)andporoustransportlayers(PTL).Thesecomponentsaccounttogetherfor50to70%ofthestackcostdependingonthedesign.Thehighcostisduetothefactthattheemployedmaterialsneedtowithstandcorrosionat2Vinacidicenvironment.Currentlyonlytitaniumisthematerialofchoicefortheanodeside.Yet, a semi-conductiveoxide layergrows its surfaceovera longperiodof time.1 In this context, alucrativesolutionistoreplacetheTiBPPsbycoatedstainlesssteel.

Weusevacuumplasmaspraying(VPS)technologytoapplyhighlystablecoatingsoftitanium(Fig.1a)andniobiumtoprotectstainlesssteelBPPsfromtheoxidativeconditionsontheanodeside.2Thelatterisabletodecreasetheinterfacialcontactresistanceandimprovesthelongtermstabilityoftheelectrolyzer.Furthermore,poroustransportlayers(PTL)canberealizedbyVPSaswell.Thesecoatingscanbeproducedonexistingtitaniumcurrentcollectorsactingasmacroporouslayers(MPL).3Lastly,freestandingmultifunctionalstructures(Fig.1b)withoptimizedtortuosity,capillarypressureandgradientporosityareusedascurrentcollectors.ThecoatingsandporousstructuresdevelopedbyVPSenablethereductionoftherequiredmaterialandcostswithoutperformancelosses.

Figure1:a)VPScoatedstainlesssteelbipolarplatewithflowfield;b)VPSproducedfunctionalporoustransportlayerwithgradientporesizedistributionandoptimizedcontactsurfacetotheelectrode.

References

1. Rakousky,C.etal.Ananalysisofdegradationphenomenainpolymerelectrolytemembranewaterelectrolysis.J.PowerSources326,120–128(2016).

2. Gago,A.S.etal.LowCostBipolarPlatesforLargeScalePEMElectrolyzers.ECSTrans.64,1039–1048(2014).3. Lettenmeier,P.,Kolb,S.,Burggraf,F.,Gago,A.S.&Friedrich,K.A.Towardsdevelopingabackinglayerforprotonexchangemembrane

electrolyzers.J.PowerSources311,153–158(2016).


62

AbstractNo.40

EUHarmornisedTestProtocolsforElectrolysisApplications

GeorgiosTsotridis

EuropeanCommissionJointResearchCentre

DirectorateC:Energy,TransportandClimatePetten,TheNetherlands

[email protected]

Summary.

Theobjectiveofthispaperistopresentasetofharmonisedoperatingconditions,testingprotocolsandproceduresforassessingperformance,durabilityandgridconnectivityofLowTemperatureWaterElectrolysisapplicationforallowingfaircomparisonoftestresultsfromvariousprojectsandlaboratories.

Abstract.

TheEnergyUnionStrategyisbuiltontheambitiontoachieve,inacost-effectiveway,afundamentaltransformationofEurope'senergysystem,movingtomoresustainable,secureandcompetitivewaysofdeliveringenergyaffordablytoconsumers.Itisalsocommittedtotransformingitstransportandenergysectoraspartofafuturelowcarboneconomy.ItisrecognisedthatFuelCellandhydrogentechnologiesholdgreatpromiseforenergyandtransportapplicationsfromtheperspectiveofmeetingEurope’senergy,environmentalandeconomicgoalsandarepartoftheStrategicEnergyTechnologies(SET)Plan-,whichwasadoptedbytheEuropeanUnionin2008.

Waterelectrolysisplaysakeyroleinalmostallscenariosforthewidespreadroll-outofhydrogenformobility,industryorenergystorage.Itisthedominantandmostefficientroutetohydrogenproductionfromrenewableelectricitysourcesandhencethemostprovenoftheoptionsforgenerationofultralow-carbonhydrogen.Electrolysisalsohastheaddedadvantageofbeingvery flexible,andhencepotentiallyadvantageous forelectricitygrids,whererapidly respondingloadscanmeettheneedsforavarietyofgridservicesinaworldofincreasingintermittentrenewablegeneration.

Theobjectiveofthispaperistopresentasetofharmonisedoperatingconditions,testingprotocolsandproceduresforassessingperformanceofLowTemperatureWaterElectrolysisapplicationsforallowingfaircomparisonoftestresultsfromvariousprojectsandlaboratories.Thedocumentalsodealswithassessmentofefficiency,durabilityanddynamicbehaviourofvariouselectrolysissystems.Durabilityisevaluatedthroughendurancetestingbyapplyingvariousloadprofilestothecell/stackandalsotosystemsforassessingthegridconnectivitycapabilities.


63

AbstractNo.41

CatalyticandPhotochemically-AssistedElectroreductionofCarbonDioxide

PawelJ.Kulesza

FacultyofChemistry,UniversityofWarsaw,Pasteura1,PL-02-093Warsaw,[email protected]

Summary.Therehasbeengrowinginterestintheelectrochemicalconversionofcarbondioxidetousefulcarbon-basedfuelsorchemicals.Thereactionproductsareofpotential importance toenergy technology, foodresearch,medicalapplicationsandfabricationofplasticmaterials.

Abstract.BecauseCO2moleculeisverystable,itselectroreductionprocessesarecharacterizedbylargeoverpotentials.Itisoftenpostulatedthat,duringelectroreduction,theratelimitingstepistheprotonationoftheadsorbedCOproductto form the CHO adsorbate. In this respect, the proton availability and its mobility at the photo(electro)chemicalinterfacehastobeaddressed.Ontheotherhand,competitionbetweensuchparallelprocessesashydrogenevolutionandcarbondioxidereductionhasalsotobeconsidered.

Recently,wehave concentratedon thedevelopmentofhybridmaterialsbyutilizing combinationofmetaloxidesemiconductorsthuscapableofeffectivephotoelectrochemicalreductionofcarbondioxide.Forexample,thecombinationoftitanium(IV)oxideandcopper(I)oxidehasbeenconsideredbeforeandaftersunlight illumination.Application of the hybrid system composed of both above-mentioned oxides resulted in high current densitiesoriginatingfromphotoelectrochemicalreductionofcarbondioxidemostlytomethanol(CH3OH)asdemonstrateduponidentificationoffinalproducts.Amongimportantissueisintentionalstabilization,activation,andfunctionalizationofthe mixed-metal-oxide-based photoelectrochemcal interface toward better long-term performance and selectivityproduction of small organic molecules (C1-C4) and other chemicals. In this respect, ultra-thin films of conductingpolymers (simpleorpolyoxometallate-derivatized)andsupramolecularcomplexes(with nitrogencontaining ligandsand certain transition metal sites), sub-monolayers of metals (Cu, Au), networks of noble metal (Au, Ag, Pd)nanoparticlesorlayersofrobustbacterialbiofilmshavebeenconsidered.

Wearealsogoing todemonstrate that thephotoinducedelectron fromsemiconductorconductionband iscapableofactivationoftheactivecenterofthemetalo-enzymemolecule.Herethe.nanostructuredsiliconmaterialhasbeenchosenasthesubstratefortheenzymeadsorption.Inthiscasethep-typeSi(111)wasetchedtowardformationofthebunchedstepsonthesurface.Thephoto-biocathodewithCu-containingenzymehasinducedthereductionofnotonlyoxygenbutcarbondioxideaswell,underilluminationswithphotonenergieshigherthansiliconbandgap.

Inthepresentation,specialattentionwillbepaidtomechanisticaspectsofelectroreductionofcarbondioxide,fabricationandcharacterizationofhighly selectiveanddurablesemiconductorphotoelectrodematerialsand to thereactionconditionspermittingeffectiveelectrolysisofcarbondioxide.


64

AbstractNo.42

Impactofthedesignonperformancelossinphoto-drivenwaterelectrolysers

FredyNandjoua,SophiaHausseneraaLaboratory of Renewable Energy Science and Engineering, EPFL

Station 9, 1015 Lausanne, Switzerland

[email protected]

Summary.Inthisstudy,wedevelopadegradationmodelinordertopredicttheperformancelossinphoto-drivenwaterelectrolysers. It appears that the durability highly depends on device design choice, on irradiation intensity in thephotoabsorber,aswellasonthecurrentdensityintheelectrolyser.

Abstract.

Photo-drivenwater electrolysis is an attractive and cleanmethod to store the solar energy directly in the formofhydrogen.As illustrated in Figure1.a, photo-drivenwater electrolysis consists of directly coupling a semiconductor(photoabsorber)toanelectrolyser,withoutneedoffurtherpowerconvertersorelectronics.Comparedtotheseparatephotovoltaicandelectrolyserconfiguration,ithasthepotentialtoincreaseenergyconversionefficiencyandtoreducehydrogen cost.When facing the problem of large scale implementation, the question arises of how to design theintegrated electrolyser in order tomaximize the cumulated amount of the produced hydrogen during the device’slifetime.Indeed,foragivenphotovoltaiccell,thedesignoftheelectrolyserwillhighlyimpactonthesolartohydrogenefficiency,aswellasonthedegradation.

Here,wediscusstheimpactofthephoto-drivenelectrolyserdesignandoperatingconditionsonperformanceloss.Aphysics-basedmodel,whichusesdegradationratesofthedevicecomponents,isusedtopredicttheperformancelossin four different illustrative device designs. One fundamental difference between commercial electrolysers andelectrolysers operatingwith photoabsorbers is the operating current density.While the former operate at currentdensitiesaround1A/cm2,the latteroperateataround10mA/cm2.Costadvantagesareusuallyobservedfor largercurrent densities (reduced use of components). In order to control current densities, radiation and/or currentconcentrationcanbeapplied[1].Examplesofi-Vcurvesobtainedduringthefirst30’000operatinghoursofthedeviceforfourdifferentcases,usingornotusingradiationconcentrationinthephotoabsorberand/orcurrentconcentrationintheelectrolyser,arepresentedinFigure1.b.Theoperatingpointofthedevice,whichdeterminestheamountoftheproducedhydrogen,istheintersectionbetweenthephotoabsorberandelectrolysercurves.Thus,atradeoffbetweenelectrolyserundersizing compared to thephotoabsorberanddurability canbe found.Furthermore, the instabilitiescausedbythesolarprofileinduceextremedynamicsinthedevice,whichareknowntoacceleratethedegradationoftheelectrolyser.Heatandwatermanagement,devicemaintenance,andcomponentreplacementcanhelpinmitigatingdegradationandthecorrespondingeffectsondeviceperformance.

Figure1.a.Photo-drivenwaterelectrolyser-b.Evolutionofthei-Vcurvesduringthefirst30’000operatinghoursof

thedeviceforfourdifferentcases,usingornotusingradiationand/orcurrentconcentration[2].

[1]DumortierM,TembhurneSandHaussenerS2015EnergyEnviron.Sci.8[2]NandjouFandHaussenerS2017J.Phys.D:Appl.Phys.50

a b


65

AbstractNo.43

SO2depolarizedelectrolyser-EnhancedH2productionwithSiCfoamflowlayer

AnnukkaSantasalo-Aarnioa,Anna-RosaTroiab,LorenzoBucchierib,SandroGianellacandMichaelGasika

aDepartmentofChemicalandMetallurgicalEngineering,AaltoUniversity,Vuorimiehentie2,FIN-00076Aalto,Finland bEnginsofts.p.A.,ViaStezzano87,I-24126Bergamo,Italy

cEngiCerSA,VialePereda22,6828Balerna,Switzerland e-mail:[email protected]

Summary. SO2 depolarized electrolyzer can produce H2 economically with reduced overvoltage and cheaper cellcomponentsthantraditionalPEMwaterelectrolyzers.InthisworkitwasconfirmedthatuseofSiCfoamprovideshighlyimprovedmixtureinanolyte,leadingtohighercurrentdensities,suppressingformationofparasiticproducts.

Abstract.Foreconomical,technicalandenvironmentalsustainabilitywaterelectrolysispoweredbyrenewablepowersourcesistraditionallyconsideredtechnique.Itrequireshoweverhighovervoltage(theoreticalE0=1.23Vvs.practical1.7-2.2 V), and therefore leads to lower efficiency, higher hydrogen costs and use of expensive PGM catalysts.Alternativeprocess-sulfurdioxidedepolarizedelectrolysis(SDE)-hasbeendeveloped,whereSO2isaddedtotheanodespaceandisoxidizedelectrochemicallytosulfuricacidfollowedbyhydrogenevolutionatcathode.SuchoverallreactionrequiresonlyE0~0.16V,i.e.severaltimesreducedvoltagevs.H2Osplitting[1].Nevertheless,oneoftheobstaclesforcommercializationistheSO2carry-overtocathodewithformationofparasiticproducts(elementalsulfurorH2S)[2].

ForSDE,materialsdesignedforwaterelectrolysisarecurrentlyused(suchaspolymerflowfieldplates),buttheyareefficientwhenliquidcarry-overphenomenonisnotpresent.Inthisstudy,chemicallyresistantSiCfoam(EngiCerSA)wastestedforiteffectonflowpropertiesinabench-scaleSDEsystem(Aalto).Theresultsconfirmedincreasedcurrentdensities in comparison to traditional inserts. Inaddition,SiC foamwas found toclearly reduce theSO2carry-over,hindering sulfur particles growth and facilitating the process control. To confirm the experimental findings, CFDcalculations for foam model (below) were made indicating that velocities and their gradients have been indeedimprovedbyseveraltimes,givingmoreefficientmixingandthereforeSO2masstransport.

Figure1.FiveCellSDEstack(Aalto)havingSiCfoam(Erbicer)asaflowfieldmaterial,andthemodeldevelopedofthe

foam(Enginsoft).

References. [1]M.B.Gorensek,J.A.Staser,T.G.Stanford,J.W.Weidner,Int.J.Hyd.Ene.34(2009)6089-6095.[2]A.Santasalo-Aarnio,J.Virtanen,M.Gasik,J.SolidStateElectrochem.20(2016)1655-1663. Acknowledgement.TheresearchleadingtotheseresultswassupportedbytheEuropeanUnion'sSeventhFrameworkProgramme(FP7),theFuelCellandHydrogenJointUndertaking,undergrantagreementn°325320oftheSOL2HY2project.Visit:https://sol2hy2.eucoord.com/


66

AbstractNo.44

SputteredPt-containingelectrocatalystsforSO2(aq)electrolysis

AFalcha,VABadetsbandRJKriekaaElectrochemistryforEnergy&EnvironmentGroup(EEE),ResearchFocusArea:ChemicalResourceBeneficiationCRB),

North-WestUniversity,PrivateBagX6001,Potchefstroom2520,SouthAfricabUniversitédeStrasbourg,CNRS,CHIMIEUMR7177,F-67000Strasbourg,France

[email protected]

Summary. Pt3Pd2 and Pt40Pd57Al3 thin film combinations were identified, by employing a high-throughput andcombinatorial(HTC)approach,aspotentialcontenderstocompetewithpurePtthatiscurrentlybeingemployedastheanodematerialinthehybridsulphur(HyS)cycleforSO2electrolysis.

Abstract.

Thehybridsulphurcycle(Figure1a),athermo-electrochemicalwatersplittingprocessthatincludestheelectrochemicaloxidationofSO2,servesasameansofproducinghydrogeninausableformwithoutemittinganyharmfulpollutants.Interestinthenon-carbon-basedHyScycleasapotentiallargescalehydrogenproductionprocessresultsfromthefactthat,whereastheanodicreactionforregularwaterelectrolysisoccursatastandardpotentialof1.23V(SHE),theanodicreactionintheSO2depolarisedelectrolyser(SDE)occursatastandardpotentialof0.17V(SHE),whichtranslatesintoanenergygainofmorethanonevoltthatmakestheHyScyclemorefavourable.AnaspectthatcanimprovetheSDEperformanceandeconomicviabilityisimprovingtheanodicreactionofelectrochemicallyoxidisingaqueousSO2.Thiscanbeachievedbyimprovingtheelectrocatalystfortheanodicreaction.

Combinatorialsputtering,high-throughputscreening,andtraditionalmethodswereemployedto investigatevariousthin filmelectrocatalystcombinationscontainingvarying ratiosofplatinum(Pt),palladium(Pd)andaluminium(Al),towardstheelectro-oxidationofaqueousSO2

1.Thecombinatorialsputteringapproach,basedonmagnetronenhancedplasmasputteringandphotolithography,wasdevelopedandemployedinthesynthesesofthethinfilmelectrocatalysts.A multi-channel potentiostat, connected to a custom manufactured multi-working electrode electrochemical cell,allowed for high-throughput parallel screening of the deposited electrocatalysts towards the electro-oxidation ofaqueousSO2.Employingonsetpotentialandcurrentoutputasthescreeningcriteriatogetherwithstabilitytestsandtheresultsobtainedfromphysicalcharacterisation,thinfilmsexhibitingsatisfactoryperformancewere identified.APt3Pd2thinfilm,annealedat800°C2,andaternarycombinationofPt40Pd57Al3,annealedat900°C

3,wereidentifiedaspotentialcontenderstocompetewithpurePtthatiscurrentlybeingemployedastheanodematerial.BothPt3Pd2andPt40Pd57Al3 thin films contain lessPt thanapurePt thin film (Figure1b),while exhibiting increasedelectrocatalyticactivity,andcanserveasabasisforfuturestudies.

a) b) Figure1:a)Thehybridsulphur(HyS)cycleandb)correlationofcurrentdensity(mA.mgPt-1)withPtcontent(%)3

References.

1. A.Falch,V.LatesandR.J.Kriek,Electrocatalysis,2015,6,322-380.2. A.Falch,V.A.Lates,H.S.KotzeandR.J.Kriek,Electrocatalysis,2016,7,33-41.3. A.Falch,V.Badets,C.LabrugèreandR.JKriek,Electrocatalysis,2016,7,379-390.


67


SteamElectrolysisastheCoreTechnologyforSectorCouplingintheEnergyTransition

OliverBormaaSunfireGmbH

[email protected]

Summary.Thesteamelectrolysiswithitssuperiorefficiencyduetotheutilisationofwasteheatisthecoretechnologytoconnecttheelectricalsectorwiththeoil&gassector.Thisleadseventuallytoadecarbonisationofallsectorsandtheachievementofthe2°Ctargetuntil2050.

Abstract.

Thedecarbonisationofthepowersectoraloneisnotsufficienttoreachthe2°Ctargetin2050,asonlyupto25%ofenergyisconsumedaselectricity.Theincreasedinstalledrenewablepowerleadstoanincreasingvolatilityinthepowerproduction,andduetothattoanecessaryovercapacityininstalledpower.Thispushestheelectricitygridunderheavyloadandleadstoanincreasingamountofcurtailedpower,especiallyfromlargewindfarms.Insteadofcurtailingthisrenewableenergy, itshouldbeshifted intotheoil&gassector inanefficientmanner.Thisenablesalsoaseasonalstorageofrenewableenergyinlargequantities.

Theefficienthydrogenproductionbyrenewableelectricityisthefirstandmostimportantstepinthesectorcoupling.Theelectricalefficiencyofthesteamelectrolysisisupto20%higherthancommonwaterelectrolysistechnologies,duetotheutilisationofwasteheatforthesteamgeneration.Wasteheatatarelativelylowtemperaturelevelofroughly150°Cisneeded,andistypicallyavailableinindustrialsurroundings,likerefineries,chemicalandmetalindustries.Thus,thedecentralisedhydrogenproductionviasteamelectrolysisinordertomitigateCO2emissionsfromSteamMethaneReformer(SMR)iseconomicallyfavourableinthoseenvironments.

Inadditiontothat,thehydrogenproductionisthecoreofallPower-to-GasandPower-to-Liquidapplications.Inthoseprocesses,theexothermicreactionenthalpyisusedforthesteamgeneration,whichmakesacombinationofsteamelectrolysisandsynthesisofdrop-infuel(syntheticnaturalgas,diesel,gasoline,kerosene,etc.)mostpromising.

Hence,thesteamelectrolysisistheoptimaltechnologytoconnecttheelectricalsectorwiththeoil&gassector.Thisleadseventuallytoadecarbonisationofallsectorsandtheachievementofthe2°Ctargetuntil2050.


68

AbstractNo.46

ElectrochemicalTailoringofSyngas

SeverinFoit1,3,VaibhavVibhu1,I.C.Vinke1,R.-A.Eichel1,2andL.G.J.deHaart11InstituteofEnergyandClimateResearch,FundamentalElectrochemistry(IEK-9),ForschungszentrumJülichGmbH,

52425Jülich,Germany2InstituteofPhysicalChemistry,RWTHAachenUniversity,52074Aachen,Germany

3e-mailofcorrespondingauthor:[email protected]

Summary:Thepresentworkisfocusedonsyngasproductionbyhigh-temperatureco-electrolysis.Bymodificationofreactionconditions,specificsyngascompositionscanbetailored.Inthisrespect,polarizationcurve,impedancespectraandproductanalysisoftheperformanceofsinglecellsarecomparedandinvestigatedindetail.

Abstract:Intheenergysystemtransition(German:Energiewende)amajorroleisforeseenforthehigh-temperatureco-electrolysisofcarbondioxideandwatervapourtosyngasbyusageofrenewablygeneratedelectricity.Syngasisusedonalargescalefortheproductionofbasicchemicalslikeammoniaandmethanol,butcanbeusedalsoforthesynthesisofsyntheticfuels,likeFischer-Tropschdieselandoxymethylenether[1].IntheSolidOxideElectrolysisCell(SOEC)thedirect reduction of water vapour, of carbon dioxide and the reverse water-gas shift reaction are the underlyingmechanisms.IntheframeworkoftheGermanKopernikusproject'Power-to-X'theco-electrolysisprocessinSOECsisinvestigatedandfurtherdevelopedtomeettherequirementsforthesubsequenthydrocarbonsynthesis,i.e.'tailoring'of the syngas compositions. Commercially available fuel electrode supported cells (CeramTec) composed of a LSCFanode,aCGObarrier-layer,an8YSZelectrolyteandaNi/8YSZcathodewereusedintheseinvestigations.Thesewereexaminedby thecombinationofelectrochemicalmethods (I/V-performance,EIS)andanall-embracingquantitativeproduct analysis. Experiments under varying conditions (temperature, current density, pure or mixed gases) wereperformed and conclusions about the competitive fundamental reactions have been drawn by comparison andcalculation.

References[1] S.Foit,I.C.Vince,L.G.J.deHaart,R.-A.Eichel,Angew.Chem.Int.Ed.(2016)10.1002/anie.201607552


69

AbstractNo.47

Systemdesignandoperationofasolidoxideelectrolyzer

LigangWanga,b,*,StefanDiethelma,JanVanherlea,FrancoisMarechalba GroupofEnergyMaterials,ÉcolePolytechniqueFédéraledeLausanne,Switzerland

bIndustrialProcessandEnergySystemsEngineering,ÉcolePolytechniqueFédéraledeLausanne,[email protected]

Summary. From the overall system perspective, the thermoneutral and exothermic operation of a solid oxideelectrolyzerachievessimilarefficiencywhileexothermicoperationwithanallowabletemperaturegradientallowsformuchlargeroperatingcurrent,thusalargerfuelproductionrateandthuspossiblyalowerproductioncost.

Abstract.Comparedwith thebestavailablealkalineelectrolyzer (2.0V,0.2A/cm2)andPEMelectrolyzer (1.8V,1.0A/cm2),asolidoxideelectrolyzer (SOEC)canoperateatarather lowvoltage (1.25-1.4V)withareasonablecurrentdensity(0.2to0.8A/cm2),achievingthusintrinsicallyhigherelectrolysisefficiencyandmoderateequipmentsize(cost).FortheoperationoftheSOECitself,thermoneutraloperationhasbeenpreferred,underwhichtheconsumedpowersatisfies the electrolysis requirement and keeps the operating temperature nearly unchanged. However, from theperspective of systemdesign, thermoneutral operation is questioned, as 1) the operating current density is low atthermoneutralvoltage,and2)afeasibleheatexchangerdesignisexpectedtoheatupthegasfeedswiththeavailableheat from theelectrolyzeroutlet.Considering these twopoints, exothermicoperationat a voltagehigher than thethermoneutralonemayofferabetterchoice.Duetotheexcesspotential,theadditionalpowerconsumedmayestablishacertaintemperaturegradientalongtheflowdirectionintheelectrolyzer.Thetemperatureincreasealongtheflowdirectionincreasestheaverageoperatingcurrentdensity.Moreimportantly,thetemperaturedifferencebetweentheelectrolyzeroutletandinletenablesbetterfeasibledesignsfortheheatexchange.Inthispaper,thethermoneutralandexothermic operationmodes of SOEC are investigated and compared to quantify the benefits from an exothermicoperationpointofviewandtofindthebestexothermicoperatingpoints.

AsmostexperimentaldataontheSOECperformanceareatconstantoperatingtemperature,theperformanceoftheexothermicoperationshouldbepredictedbymodellingtoareasonableprecision.Aquasi2Dmodelconsideringmasstransfer along electrodes by the dusty gasmodel, current-density distribution along the gas channels and detailedoverpotentialcalculation,hasbeendevelopedandcalibratedwithexperimentaldataforSOLIDPowerSOECofsteamelectrolysiswithafeedcomposition(H2O/H2:0.9/0.1)atbothatmosphericandelevatedpressuresandco-electrolysiswithvariousfeedcompositions(H2O/H2/CO2:0.8/0.1/0.1,H2O/H2/CO2:0.65/0.1/0.25,H2O/H2/CO2:0.45/0.1/0.45)atatmospheric pressure. The calibrated model could predict the experimental electrolysis performance with goodaccuracy.Itishenceassumedthatthismodelprovidesareasonableperformancepredictionforexothermicoperation.

Asisknown,forSOECthesteamcannotbeconvertedtoveryhighratestoavoiddegradation,thusitsutilizationfactorisrecommendedtolieintherangeof60-80%.Thehigherthisutilizationfactor,thehighertheoverallsystemefficiencywillbe.Forthermoneutraloperationat700Candautilizationfactorof80%,theoperatingvoltage,averagecurrentdensityandfeedflowratearecalculatedas1.28V,0.3695A/cm2and 3.59NmLPM/cm2,respectively.Whilefortheexothermicoperationatthesameutilizationfactor(80%),afeedtemperatureof700°Candatemperaturedifferenceof 110 °C between the electrolyzer outlet and inlet, the operating voltage, current density and feed flowrate arecalculated as 1.339 V, 0.716 A/cm2, 6.94 NmLPM/cm2. It can be shown that with the same utilization factor thethermoneutralandexothermicoperationofasolidoxideelectrolyzercanachievethesamesystemefficiency,whiletheexothermicoperationallowsasignificantlylargeroperatingcurrent,thusalargerfuelproductionrateandthuspossiblyalowerproductioncost.Particularly,forthesameareaofelectrolyer,thetotalpowerstoredisdoubledbyexothermicoperation with an outlet-inlet temperature difference of 110 °C, compared with thermoneutral operation. Thus,exothermicoperationcanberecommendedforcost-effectivedesignandoperationofastandaloneSOECsystem.

TheresearchleadingtotheseresultshasreceivedfundingfromtheEuropeanUnion'sSeventhFrameworkProgramme(FP7/2007-2013)fortheFuelCellsandHydrogenJointTechnologyInitiativeundergrantagreementn°621173,SOPHIA.


70

AbstractNo.48

SolidoxideelectrolyzessystemdevelopmentRichardSchauperla,BeppinoDefneraandJuergenRechbergera(pleaseunderlinepresenter)

[email protected]

Summary.

Various advantageous system concepts for SOEC, Co-SOEC and rSOEC systems including all componentswhich arenecessarytooperatethehightemperatureelectrolysisstack,wereidentified.Validatedsystemconceptsonthetestrigwillbepresented,reachingelectricaltochemicalenergyconversionefficienciesupto80%.

Abstract.

Power-to-Gas-to-Power technologies offer strong potentials for energy markets with highly stochastic energyproduction from renewable sources, such as wind and PV. Electrical energy can be stored in chemical energy byproducingmolecularhydrogenorsyngas.Thishappensviaelectrolysisofsteamorco-electrolysisofsteamandcarbondioxide.Theseenergycarrierscaneitherbeusedasabufferforfluctuatingenergyproduction,orusedastransportfuels.Thesyntheticfuelsarepotentiallycarbonneutral,whentheelectricitycomesfromrenewableenergyproduction.

Increasingefficienciesandcosteffectivenessarekeyissuesinstateoftheartsolidoxideelectrolyzessystemsandstillamajorchallenge.Averycosteffectivesolutionisusinginsteadoftwoseparateunitsthatoperatealternatelyforgasor power production, a reversible SOE system (rSOE). The rSOEC system can switch between these two operationmodes,whichresultsinamorecompactsystemthatcanbeoperatedalmostfulltime.Additionally,thesystemcanbehighlyefficientoperatedwithawholerangeofdifferentfuels,whichincreasesthetechnologiesflexibilityandusability.

ThismultiuseandmultifuelcharacterofSOEsystemsleadstoveryparticularchallengesinthedevelopment.AfeasibleconcepthastocombineallnecessaryBoPcomponentsandcontrolmechanismsallowingallmodesofoperation,whilekeeping efficiencies and cost effectiveness.One particular challenge for the systemdesign is heatmanagement. Amethodwasdevelopedthatpromisesbestpossibleuseofheatrecirculationinallmodes,whilebeingminimalindesignandregulationrequirements.Forthefirsttimedynamicsimulationsforalloperatingconditionse.g.start-up,shut-down,stand-byandmode-switchingprocesses, includingall relevantmassandenergy flowsarecurrentlydeveloped.Thisstronglysupportsthesystemdevelopmentbymakingthemmoreeffective,sinceiterativedevelopmentcirclesandthusdevelopmenttimeandhardwarecostswerereduced.

Theproject“Hydrocell”(2013-2016)demonstratedtheusabilityofthesesimulationmethods.AProof-of-ConceptSOECsystemhasbeendevelopedandtestedwithelectricitytoH2(LHV)conversionefficienciesabove80%el.

Withinthecurrentproject“AuRora”,varioussystemdesignsforafullyautonomousrSOEsystemwereidentified.Theconcepts are switchable between H2O electrolysis, H20+CO2 co-electrolysis with system integrated catalyticmethanationandmultifuelSOFCoperation.Systemconceptsaredevelopedwithconversionefficienciesabove80%el*forH2productionandCH4production.Basedonthesimulationresults,includingCFD,a1kWelProof-of-Conceptwillberealizedonthetestrigin2017.

Within thepresentation, the theoretical background, different SOE and rSOE systemsdesigns, optimizedoperationconditions,aswellassystemmeasurementsperformedintheproject“Hydrocell”and“AuRora”willbeexplained.Thisincludessteam-electrolysis,H2O+CO2co-electrolysiswithsystemintegratedcatalyticmethanation,SOFCoperationwithH2,aswellasmultifueloperationwithsystemintegratedfuelreformation.

*basedonLHVenergycontent


71

AbstractNo.49

ElectrochemicalCharacterizationofa10layerSolidOxideElectrolysisStackoperatedunderpressurizedconditions

MarcRiedel,MarcP.Heddrich,K.AndreasFriedrich

GermanAerospaceCenter(DLR),InstituteofEngineeringThermodynamics,Stuttgart,[email protected]

Summary.

Acommerciallyavailableplanar10layersolidoxideelectrolysisstackwithelectrolytesupportedcellswascharacterizedinanoperatingpressurerangebetween1.4and8bar.Current-voltagecharacteristicsand impedancespectroscopywerecarriedoutbyvaryingreactantgascomposition,steamutilizationandoperatingtemperature.

Abstract.

The major part of the prospective power supply system will be based on solar and wind energy. The associatedintermittency of energy supply due to varying weather conditions requires flexible storage and usage options.Convertingelectricalintochemicalenergycouldbeanessentialconstituentinthischallenge.Onepromisingpathisthesolidoxideelectrolysiscell(SOEC)technologywhichcanhighlyefficientlyprovidechemicalslikehydrogenorderivedhydrocarbonsfromelectricity.Theseproductscanbeusedasfuelsinmobility,forthechemicalprocessindustry,forconversionbacktoelectricityorheating.SOECsofferagreatpotential forahighlyefficientenergyconversiondue to theirhighoperating temperature.Fastkineticsofelectrochemicalreactionsleadtoreducedelectrochemicallosses.Additionally,previousstudieshaveshownthattheefficiencyofsolidoxidecellscanbesignificantlyimprovedbyoperatingatelevatedpressure[1,2].Afurtherreasonforpressurizationistheuseofpressurizedhydrogenindownstreamprocesseslikestorageorfuelsynthesis.ExperimentalresultsofaSOECstackoperatedunderpressurizedconditionsinwaterelectrolysismodearepresented.Foraparameterstudyacommerciallyavailableplanarstackconsistingof10electrolytesupportedcellswasused.Thestackwas operated in a pressure range between 1.4 and 8 bar. Parameter sensitivitieswere examined by varyingreactantgas composition (xH2O=0.80…0.98), steamutilization (0.60…0.85)andoperating temperature (750…850 °C).Pressureinfluenceonopen-circuitvoltage(OCV)andreachablepowerdensitywasexaminedonthebasisofcurrent-voltage curves. Impedance spectroscopywas carriedout for further investigations todistinguishbetweendifferentelectrochemical phenomena. Whereas the impedance measurements show strong influences on severalelectrochemicalandphysicalprocesses,current-voltagecurvesshowonlysmallchangesduetothecomparably lowcurrentdensitiesreachablewithelectrolytesupportedcells.[1]S.Seidler,JournalofPowerSourcesVol.196,7195-7202(2010)[2]L.Bernadet,ECSTransactionsVol.68,3369-3378(2015)


72


TheDevelopmentofAcceleratedStressTestsforPEMElectrolysers

AntoninoAricob,JamesDodwella,RachelBackhousea,NicholasvanDijkaaITMPower(Research)Ltd,UnitH,SheffieldAirportBusinessPark,EuropaLink,SheffieldS91XU,UK

bConsiglioNazionaleDelleRicerche,CNR-ITAEInstitute,ViaSalitaSantaLuciasopra,Contesse,5,98126-Messina,[email protected]

Summary.Anunderstandingofdegradationmechanismsofkeymaterials(catalyst,membraneandbipolarplates)inPEMelectrolysersisimportanttogetinnovationstomarketfaster.Alongwithmechanisms,theacceleratedstresstestsdevelopedtotestthesewillbediscussed.

Abstract.Inaworldinwhichfossilfuelenergyisbecomingevermorescarceandexpensiveandcountriesarestrugglingtomeettheircarbonreductionobligations,hydrogensolutionshavefinallyreachedthetopofenergyagendas.Theonlyindustrially applicable zero carbon method to produce hydrogen is via electrolysis utilizing renewable sources ofelectricity.

ITMPowerisattheveryheartoftheinitiativesandprogrammestoadopthydrogentechnologythatwillreducebothcarbonfootprintsandenergycosts.Usingitstechnologyandknow-how,ITMisaimingtobetheworldleadingsupplierofbothinfrastructurefortheproductionofgreenhydrogentransportfuel,andproductsforthegenerationandstorageofhydrogenfuelfromintermittentrenewableenergysources.

PEMelectrolysershavealifetimeof5-10years;assuchthereisdifficultyingettingnewmaterialstomarket.Inordertoget innovations tomarket faster the failuremechanismsneed tobewellunderstoodandmethods toacceleratedegradation,basedonrealfailuremechanismsneedtobedeveloped.

The first step is to understand themodeof operation of electrolysers in the field. The key is electrolysers (almostindependentofapplication)needtobeofffor longperiodsoftimeandneedtobeabletorespondonasubsecondbasis. This verydifferent tohowmost electrolysers are tested in the laboratory steady state and intermittent loadfollowingarecommonpractice.Thereasonsbehindthiswillbeexplainedinmoredetail.

Inaddition,thestackfailuremechanismswillbediscussedandhowthesearemeasuredinthelaboratory.InonesuchexampleITMhaveusedanin-situreferenceelectrode(developedincollaborationwiththeNationalPhysicalLaboratory)tohelpunderstandcatalystdegradationwithinthecell.Thisapproachenablesseparationoftherelativecontributionsofanodeandcathodetotheoverallreaction.Duringshutdownperiods,itwasobservedthatthecathodecontributesmoretochangesintheopencircuitvoltage.Thisknowledgehasbeenusedtoshowthatthemajorityofthedegradationisoccurringonthecathodecatalyst,whichisincontrasttotheperceivedthoughtwhichassumestheanodedegradesfaster.Changesintheelectrochemicallyactivesurfaceareaoftheplatinumcathodeasaresultofpotentialcyclingweredetermined in-situ via hydrogen underpotential cyclic voltammetry. Scanning electron microscopy and X-raytomographywereused tocorrelatechanges incatalystmorphologywithperformancedegradationofbothcarbon-supportedandunsupportedplatinumcatalysts.Theseexperimentshaveledtothedevelopmentofacceleratedstresstests,basedoncyclingoftheelectrodepotential,forPEMelectrolysercatalysts.Othersuchexampleswillbepresented.

Acknowledgement

This project has received funding from the FCH JU and European Union’s Horizon 2020 research and innovationprogrammeundergrantagreementNo700008.This JointUndertakingreceivessupport fromtheEuropeanUnion’sHorizon2020researchandinnovationprogrammeandHydrogenEuropeandN.ERGHY.


73


BenchmarkingCatalystActivityandDurabilityforWaterElectrolysis

HuiXuandCortneyMittelsteadtGinerInc.,

89RumfordAvenueNewton,MA02466

Email:[email protected].(Giner)hasbeenaworldleaderinresearching,developingandmanufacturinglowtemperaturewaterelectrolyzers.Advancedcatalystshavebeendevelopedtoenhancetheperformanceofwaterelectrolyzerswhileloweringtheircapitalcost.Benchmarkwaterelectrolysiscatalystperformanceanddurabilitywillbeestablished.

Abstract.Theutilizationofrenewableenergyhassubstantiallydriveninvestmentsintowaterelectrolysis.Asrenewableenergyemergesandpenetratesfurtherintotheenergymarket,thestorageofsurplus“offpeak”electricityhasreceivedwidespreadattention.Anelectrolyzercanutilize“offpeak”electricityfromsolarorwindfarmstoproducehydrogen(H2).Thishydrogencanthenbeoperatedinafuelcellmodetogenerateelectricitywhenneeded.Itisestimatedthatthewaterelectrolyzermarketcanriseupto300GWoverthenexttwodecades. Thepowertogasmarketaloneispoisedtobecomeamulti-billiondollarmarketforon-sitewaterelectrolysissystemsoverthenextdecade.

However,currenthydrogenproductionfromelectrolysiscomprisesonlyasmallfractionoftheglobalhydrogenmarketduetothehighcostthatresultsfromexpensivematerialsevenif“free”electricityfromrenewableenergycanbe acquired. Ginerhasbeenaworld leader in researching, developing andmanufacturing low temperaturewaterelectrolyzersand reversible fuel cells.Wehavebeenstriving toaddress thechallengesof thesematerials (catalyst,membrane,andbipolar)toimproveelectrolyzers’performance,extendtheirlifetime,andlowertheircapitalcost.Theseeffortsinclude:1)loweringplatinum-groupmetal(PGM)catalystloading;2)discoveringnon-preciousmetalcatalysts;3) improvingmembranedurability;4)reducingH2crossoveracrossmembrane;5) increasingcorrosionresistanceofseparatorsandotherhardware.

InParticular,catalystactivityanddurabilityplayanessentialroleforthecostandviablecommercializationofwater electrolysis. In the fieldof protonexchangemembraneelectrolysis,Ginerdevelops advanced Ir nanoparticlecatalysts that, in a comparison with commercial catalyst, has successfully lowered the Ir loading by an order ofmagnitudewhileretainingasimilarperformance.ThestabilityoftheadvancedIrnano-catalysthasalsobeenexamined,whichisfoundedtobetremendouslyimpactedbyprocessingconditionsamidcatalystsynthesis.Inthefieldofalkalinemembraneelectrolysis,Ginerhasdevelopedbifunctionaloxygenreductionreaction(ORR)/oxygenevolutionreaction(OER),Co3O4supportedoncorrosion-resistantcarbontubes,whichenablestheoperationofreversiblefuelcellswithextendedhours.

Unlike the well-established catalyst benchmarks of fuel cells, the performance and durability of waterelectrolyzer catalyst have not been thoroughly studied. We aim to establish benchmark catalyst performance anddurabilityforlowtemperaturewaterelectrolysis.Forthispurpose,aseriesofoxygenevolutionreaction(OER)catalysts,whichincludescommercialIrblackandvariousIrnanostructures,willbeevaluatedundertestprotocolsestablishedatGinerInc.Theseapproachesincludehigh-voltagehold(>1.8V),voltagecycling(1.4to2.0V),andconstantlow-currentoperations. ThepolarizationcurvesoftheMEAswillbeobtainedaftereachtest. ThemorphologyandstructureofMEAsafterdurabilitytestswillbecharacterizedtocorrelatetotheirperformanceanddurability.

Someoftheseadvanceshavebeenappliedinourelectrolyzerproducts,fromsmalllabhydrogengeneratorstoMWstacks.Theperformanceandefficiencyofourelectrolyzersarethustremendouslyimproved.ThedevelopmentanddeploymentoftheseMWelectrolyzerstackswillcultivatethelarge-scalestorageandapplicationofavarietyofrenewableenergy.


74

AbstractNo.52

Operationoflow-tempelectrolyzersatveryhighcurrentdensities:apipedreamoranopportunity?

KrzysztofLewinskia,FuxiaSuna,SeanLuopaa,JiyoungParka,andRichMaselbaCorporateResearchMaterialsLaboratory,3MCompany,Bldg.201-01-C-30,St.Paul,MN,UnitedStates

bDioxideMaterialsCompany,3998FAUBLVD,#300,BocaRatonFL,[email protected]

Abstract.Recently introduced3MNSTF-basedelectrolyzer specific catalysts andCCMswere shown tobe excellentperformersinelectrolysismode,particularlyattheveryhighcurrentdensityranges,withcurrentdensitiesapproachingashighas20A/cm2werereported(1)InadditiontotheexcellentperformancethesecatalystsareabletoachievethisperformancewithunrivalledlowPGMuse,typicallyaround1/10thofthetypicalcatalystloadingsusedinconventionalPEMelectrolyzers.Surprisingly,theperformanceattheselowloadingsseemtohavenoilleffectsondurabilityofCCMsbasedonthesecatalystsasdemonstratedinrecentpresentations(2,3),evenwhentheoperatingtemperatureofthecellwasraisedto80°Candbeyond.

Theseadvancesmayopenthewaytosuccessfullyaddressglobalenergystoragemarketswheresizablepenetrationofrenewable energy generating sources start to introduce stress on the existing power grids(4). By coupling theelectrolyzerstotherenewableenergygenerators(wind,solar,tide,etc.)onecandecouplegenerationandstorage(viahydrogenstorageintanks,caverns,gasfields,etc.)andbettermatchenergysupplytoenergydemand.Tosuccessfullydothathowever,relativelyinexpensiveelectrolyzersmayneedtobeused,astheyarepredictedtobeutilizedonlyinthe fraction of the day when electricity prices are depressed by overproduction from renewable sources (hencerelativelyhigherperkWcapitalcosts).Webelievethebestwaytolowerthecapitalcostoftheelectrolyzeristooperateoneathighcurrentdensityrange(largedynamicwindow),thuseliminatingtheneedformultipleelectrolyzerunits.

Canthisbeachieved?Oristhisjustapipedream?

Ourpresentationwilldiscuss resultswhere3MNSTFelectrolyzerCCMswereevaluatedat relativelyhighcurrentdensitiesunderadurabilitytest,includingoperationashighas10A/cm2for5000hours.We’llalsotaketheopportunitytointroduceourcollaborationwithDioxideMaterialsandpresentnewandinterestingdataonhighperformanceelectrolysisinalkalineenvironments.

AllPEMdatatobepresentedwere/willhavebeenobtainedwithIr-NSTFandPt-NSTFelectro-catalystontheanodeandcathodesidesrespectively.AfuelcelltechnologyhardwarewithgraphitecathodeandTimadeanodewith50cm2activemembraneareawasusedinalltheexperiments.

1. KrzysztofA.Lewinski,SeanM.Luopa,(invited)“HighPowerWaterElectrolysisasaNewParadigmforOperationofPEMElectrolyzer”(abstract1948),SpringECSMeeting,Chicago,IL,May2015.

2. KrzysztofA.Lewinski,DennisvanderVliet,andSeanM.Luopa,“NSTFAdvancesforPEMElectrolysis-theEffectofAlloyingonActivityofNSTFElectrolyzerCatalystsandPerformanceofNSTFBasedPEMElectrolyzers”(Abstract1457),FallECSMeeting,Phoenix,AZ,Oct2015.

3. KrzysztofA.Lewinski,DennisvanderVliet,andSeanM.Luopa,“NSTFAdvancesforPEMElectrolysis-theEffectofAlloyingonActivityofNSTFElectrolyzerCatalystsandPerformanceofNSTFBasedPEMElectrolyzers”,(10.1149/06917.0893ecst),ECSTransactions,69(17),p.893-917(2015).

4. BryanPivovar,"H2NRELWorkshopatScale:EnhancetheU.S.energyportfoliothroughsustainableuseofdomesticresources,improvementsininfrastructure,andincreaseingridresiliency.",NRELWorkshop,November16,2016(https://energy.gov/sites/prod/files/2016/12/f34/fcto_h2atscale_workshop_pivovar_2.pdf)


75

AbstractNo.53

Membranesforrecombinationandelectro-oxidationofpermeatedhydrogeninPEMelectrolysis

DmitriBessarabova,AndriesKrugeraaHySAInfrastructureCenter,North-WestUniversity,PrivateBagX6001,Potchefstroom,SouthAfrica

[email protected]

Summary.Recombinationandelectro-oxidationofpermeatedhydrogenwillresultinreductionofitsconcentrationintheanodecompartmentofPEMelectrolysers.Inordertoachievethishydrogenconcentrationreduction,PFSA-basedmembranesweremodifiedbydepositingplatinumnanoparticleswithinthemembranestructure.

Abstract.TheoriginofthehydrogenintheanodesectionofPEMelectrolyserisduetothepermeationoccurringfromthe cathode compartment. This talk will provide some data and theoretical analysis on the use of platinum (Pt)nanoparticleswithinthePFSAmembranematrixtoreducehydrogenconcentrationduringPEMwaterelectrolysis.

Depositionofplatinumparticleswasachievedbyproprietaryelectro-lessreductiontechnique.

Commercially available PFSA-based membranes were used. The membrane structure was modified by platinumnanoparticles.All-titaniummadeelectrolysiscellwith25cm2activemembraneareawasusedinalltheexperiments.Thepermeationrateofhydrogenfromcathodetoanodecompartmentwasmeasuredbygaschromatographymethod.TheeffectofPtpresencewithinthemembranestructureontheconcentrationofhydrogenintheoxygenstreamwasassessed.Temperaturesaswellaswatersupplyrateandcurrentdensitieswerealsousedasexperimentalvariables.


76

AbstractNo.54

Physicalfactorsaffectinggas-leakagefromPEMWEYutaTsuchiyaa,AkikoInadaa,HironoriNakajimaa,andKoheiItoa

aDepartmentofhydrogenenergysystem,[email protected]

Summary.

SealingtechnologyiscriticaltocommercializehighpressurePEMWE.Representativeparameterstodeterminesealingperformance isexperimentallyexaminedwithTAGUCHImethod.Among theparameters, cathodepackingmaterial,surfaceroughnessofPEMandO-ringhardnessaredominantfactorstodeterminethesealingperformance.

Abstract.

SealingtohighlypressurizedgasinPEMWEisgenericallydifficult.Differentfromconventionalsealinginmetallicpipinganditsjoints,thesealingmaterialsembeddedinPEWEMfacesdifferentkindsofmaterial,andthegasleakageoccursattheinterfacebetweenthematerials.Oneofthematerialsissupposedtobepolymerelectrolytemembrane(PEM).PEMshrinksandexpandsinratherlargeextent,accordingtodegreeofhydration.Inaddition,thesurfaceofPEMhasaroughness,whichispredictedtoworsesealingperformance.Moreover,PEMindicateshighacidnature,whichsuggestscorrosion-resistivematerial as sealingmaterial. These specific characteristic causedifficulty indevelopingadequatesealingmethodforPEMWE.

Thisstudypicksupphysicalfactors,whicharepredictedtoaffectgas-leakage,andevaluatestheimpactoftheeachfactoronthegas-leakagefromPEMWEcell.Sevenfactors,suchasO-ringhardnessandPEM,arepickedup.Gas-tightnesstest,inwhichthecelliscomposedofaspecificpairofthefactors,isexecutedandrepeated.Thetestidentifieswhichfactorsignificantlyimpactsongas-leakage.Taguchimethodisintroducedtogiveanefficiency,whichreducesthenumberoftimesunderdifferentpairoffactorforthegas-tightnesstest.Inaddition,theloadimposedonO-ringaremeasuredwithpressure-sensitive-film.TheloadtoO-ringisthoughttodirectlydeterminepathofgasleakageandthustheflowrateof thegas leakage.Furthermore, impactofsealingfactoroncontactelectrical resistance isevaluated.Inappropriatesealingmanner,suchastoolargewirediameterofO-ringandtoolowtighteningpressure,causesagapbetweencellcomponents,resultinginanincreaseofthecontactresistance.Throughtheabovesuccessiveevaluations,dominantfactorsandpropersealingmethodisdiscussed.


77


Polyaromatic,SolidPolymerElectrolytesforAcidicandAlkalineElectrolyzers

StevenHoldcroft

DepartmentofChemistry,SimonFraserUniversity,8888UniversityDrive,Burnaby,

GreaterVancouver,BC,V5A1S6,[email protected]

Summary.Aredurablehydrocarbonproton-andhydroxide-conductingsolidpolymerelectrolytesattainable?

Abstract.Perfluorinatedproton-exchangepolymersformthebasisofstandardhigh-performancePEMelectrolyzersbutdifficultsyntheticchemistryhampersfurthermaterialsdevelopment.Hydrocarbonproton-exchangematerials,ontheother hand, are founded on well-established and versatile synthetic chemistry that allows for rapid materialsdevelopment,andofferalessexpensivealternativetoperfluorinatedpolymers.InthecorollarycaseofAnionExchangeMembrane electrolyzers, the search continues for an alkaline-stable, polymeric hydroxide-conducting medium.Solutions to these challenges require the undertaking of rigorous systematic studies on model polymers andrepresentative materials of known and controllable molecular structure and preferred nano-morphology. In thispresentation,thepropertiesofuniqueproton-andhydroxide-conductingpolymerswillbedescribed.


78

AbstractNo.56

Recentdevelopmentsinalkalinepressureelectrolysiswithanion-conductivemembrane(AEM)

UlrichR.Fischera,DanielTannerta,AndréVoigta,ChristianZiemsaandHans-JoachimKrautzaaBrandenburgUniversityofTechnology(BTU)Cottbus–Senftenberg,Germany

[email protected]

Summary.An overview of recent developments in alkaline pressure electrolysis with anion-conductivemembrane(AEM)andtheadvantagesanddisadvantagesofthetechnologyisgiven.Thetargetsofourcurrentresearchprojectinthisfieldareintroduced.

Abstract.Research in alkalinemembrane electrolysis with an anion-conductivemembrane (AEM) has experiencedincreasedattentioninthelastyearsduetoitsperspectivetocombinepositivefeaturesofboththecommonalkalineandPEM-waterelectrolysis[1-3].TheAEMelectrolysisusesananion-conductivemembranewhichactsasseparatorandelectrolytesimultaneously.Manyadvantagesresultfromthisspecificproperty.Itispossibletointroduceazerogapdesignwiththeworkingelectrodesadhereddirectlytothemembranewhichinturndecreasestheovervoltagesandincreases thecurrentdensity.Furthermoreonlyaweak lyeorevenpurewater isnecessary insteadofahazardousstronglye.Distilledwaterhastobefedonlytothelowpressureanodeside.TherearelowerrequirementsconcerningthefeedwaterqualityincomparisontoPEM-electrolysis.Nowatercircuit isnecessaryatthecathodesideandhighpressurehydrogenup to30bar is releasedwitha very lowwater vapor content in the rangeof a fewppm [4]. IncomparisontothePEMelectrolysisawiderrangeofnon-noblecatalystsisapplicable[5].Themorecompactandsimplesystemdesignwithcheapmaterialscansignificantlyreducemanufacturingcosts.Besidetheseadvantagesthecompactdesignoffersthepossibilitytoapplyhigherworkingpressuresandtogainanadditionalbenefitinconcernofenergyconsumption[6].

Butthereisyetresearcheffortnecessarytoimprovetheinsufficientstabilityoftheavailableanion-selectivemembranesunder the conditions of water electrolysis. Membranes have to fulfill various requirements concerning high ionicconductivityandlong-termmechanicalandchemicalstability.Theoperationisstillrestrictedtotemperaturesbelow70°C. The membranes which contain positively charged ionic groups for the ionic conductivity exhibit insufficientmechanicalstabilityyetifthenumberofionicgroupsistoohigh.AtourHydrogenResearchCentreaprojectwasstartedwithfocusontheapplicationofanion-conductivemembranesinpressureelectrolysis.InthecourseoftheprojectAEL-MALFE(alkalineelectrolysiswithsolidanionconductiveelectrolyte)thesetupofanewtestcellisaimed.Thedesignandconstructionof the test facility isbasedonoperationalexpertise fromapressurisedalkalineelectrolyserandasinglecelltestrack.Differentconceptsofcelldesignanddifferentmaterialcombinationswillbeevaluated.

[1] M.Bodner,A.Hofer,V.Hacker:H2-Generationfromalkalineelectrolyzer.WIREsEnergyandEnvironment,Vol4,2015,JohnWiley&Sons,pp.365-381

[2] M.Manolova,C.Schoeberl,R.Freudenberger,C.Ellwein,J.Kerres,S.Stypka,B.Oberschachtsiek:Developmentandtestingofananionexchangemembraneelectrolyser.InternationalJournalofHydrogenEnergy40(2015)11362-11369

[3] J. Kapischke, D. Jarosch: Development, construction and testing of awater electrolysis cellwith anion exchangemembrane. iSEneC-Integrationofsustainableenergyconference,Nürnberg2016

[4] C.C.Pavel,F.Cecconi,Ch.Emiliani,S.Santiccioli,A.Scaffidi,S.Catanorchi,M.Comotti:Highlyefficientplatinumgroupmetalfreebasedmembrane-electrodeassemblyforanionexchangemembranewaterelectrolysis.Angew.Chem.Int.Ed.2014,53,Wiley-VCH,pp1378-1381

[5] M.Paidar,V.Fateev,K.Bouzek:Membraneelectrolysis–History,currentstatusandperspective.ElectrochimicaActa209(2016)737-756[6] U. R. Fischer, A. Voigt, D. Tannert, C. Ziems, H. J. Krautz: Pressure and Temperature Influence on Alkaline Water Electrolysis

Performance.5thEuropeanFuelCell&H2-Forum,Luzern


79

AbstractNo.57

Anionselectivemembranesbasedlaboratory-scalealkalinewaterelectrolysisstack

JaromirHnata,RomanKodým,MartinPaidara,JakubRutrleandKarelBouzeka

UniversityofChemistryandTechnologyPrague,Technicka5,16628,Prague,CzechRepublic;tel.:[email protected]

Summary.Laboratory-scalealkalinewaterelectrolysisstackwasdeveloped,constructedandoperatedunderdifferentconditionsutilisingdifferenttypesofionselectivepolymermembranes.Influenceofthetypeofthepolymermembraneandoperationalconditionsontheelectrolysisvoltage/currentefficiencyandgasespuritywerefollowed.

Abstract.Waterelectrolysisrepresentsthemostwidelyusedmethodofwatersplittingunderhydrogenandoxygenevolution.Itseparatestheoverallreactionintotwohalf-cellreactionsinwhichhydrogenandoxygenarereleasedfrommoleculeofwaterbyindividualelectrodereactions.Suchseparationisnecessaryinordertoreachhighproductpurityandprocessefficiency,aswellastooperatetheprocesssafely.Processefficiencyisstronglyrelatedtothecellvoltageneededtoruntheprocessunderdesired intensity.Theoreticaldecompositionvoltageofwaterof1.23Vat25°C isunderrealconditionsshiftedtotheoperationalvalueof1.7–2.0V.Thereasonforthisincreaseistwo-fold:(i)ohmicvoltagelossand(ii)electrodereactionsovervoltage.PEMwaterelectrolysisutilizesprotonexchangemembrane(PEM)asaseparatorofcathodeandanodecompartmentsandapolymerelectrolyteinone.Itallowsusing“zero-gap”celldesignreducingthusimpactofthefirstreasonofincreasedvoltage.Itisbecauseitreducesinterelectrodedistanceandeliminatesdangerofgasphaseaccumulationinthespacebetweentheelectrodes.Unfortunately,similarmaterialsarenotgenerallyavailableforthecaseofalkalinewaterelectrolysis.Thus,aporousseparator(diaphragm)istypicallyused.Theapplicationofporous inorganicororganicdiaphragmas separatorof theelectrodescompartmentshas severalnegative consequences. It includes, besides increased ohmic drop, a need to use significant volumes of highlyconcentratedKOHsolutionasanelectrolyte.Itisthereforedesirabletoreplacediaphragmbyanionselectivepolymerelectrolyteseparator.Suchasetupallowsutilizingofthezero-gapresultinginKOHelectrolyteconcentrationreductionalsointhecaseofthealkalinewaterelectrolysis.Thischangeincreasessafetyandflexibilityoftheprocess.Atthesametime,duetothereducedconductivityoftheliquidelectrolyte,importanceoftheparasiticcurrentsisincontrasttothetraditionalstackarrangementreduced.Additionally,itispossibletousetheelectrodesmodifiedbythesuitablecatalyticlayer,utilizinganionselectivematerialsasbindersandthusachievefurthervoltagelossesreduction.

Thepresentstudyisfocusedondevelopmentofthelaboratoryscalezero-gapalkalinewaterelectrolysisstackutilizingionconductivemembrane.Electrodesofthegeometricalactivesurfaceareaof25cm2wereused.Mathematicalmodelevaluating influence of the distribution channels and flow plate design on the electrode chambers flooding andoccurrenceoftheparasiticcurrentswasdeveloped.Itwasbasedoncalculationoftheonephaseflowinordertogettheprimaryinformationontheliquidelectrolytedistributionintheeachcellofthelaboratoryscalestack.Atthislevelmodelsupposestheinertialforcestobenegligibleandcalculatesonthebasisofthemassandkineticenergybalance.Efficiencyoftheproducedgasphaseremovalwasoptimisedexperimentally.Voltage/currentcharacteristicsandpurityof the gasses producedby thedesigned stackwere followed for heterogeneous andhomogeneous anion selectivepolymermembrane. The results were compared to the commercially available Nafion cation selectivemembrane.Achievedresultsoftheexperimentalpartshowedthepotentialtoachieveindustrialvaluesoftheelectrolysisvoltageefficiency undermilder conditions (lower temperature andKOH concentration) andhigh current efficiency even atrelativelylowcurrentdensities.

Acknowledgement

FinancialsupportofthisresearchbytheGrantAgencyoftheCzechRepublicwithintheframeworkoftheprojectNo.16-20728Sisgratefullyacknowledged.


80

AbstractNo.58

HighTemperatureMembranelessAlkalineElectrolysis

JeremyHartvigsen

[email protected]

Summary. Performance of a high temperature membraneless alkaline electrolysis. Increasing the operatingtemperatureallowsfortheuseofnon-preciousmetalcatalysts,whileincreasingoverallperformance.

Abstract.Recentworkhasbeenperformedonmembranelessandhigh temperaturealkalineelectrolysis.Thisworkbuildsonpreviousworkdonebychangingthematerialsofconstructioninordertoreachhighertemperatures.

Theactivityofnickelelectrodesabove150°Cisadramaticimprovementoveroperationat80°Cwheremostcommercialelectrolyzersoperate.Thetypicallimitingfactorinincreasingtemperatureisthemembrane.Anovelflow-basedproductseparationisusedtopreventproductmixing.Previousresultshaveshownthatthismixingcanbeminimizedtolevelscomparablewithstandardalkalinemembranes.Byincreasingthetemperaturefurtherto200-250°Cthesystemcanoperateatornearthethermalneutralvoltage.Thisreducedthecooling loadneededfortheelectrolyte,aswellasreducingtheoverallenergyconsumption.Performanceinthisregionisthefocusoftheworkpresented.


81

AbstractNo.59

AlkalinemembraneelectrolysiswithPEM-levelelectrochemicalperformance

MikkelRykærKraglunda,MarceloCarmob,DavidAilia,GüntherSchillerc,ErikChristensena,AndreasFriedrichc,DetlefStoltenb,d,JensOlufJensena

aDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,DK-2800Kgs.Lyngby,DenmarkbInstituteofEnergyandClimateResearch,IEK-3:ElectrochemicalProcessEngineering,ForschungszentrumJülich

GmbH,52425Jülich,GermanycInstitutfürTechnischeThermodynamik,DeutschesZentrumfürLuft-undRaumfahrt(DLR),70569Stuttgart,Germany

dChairforFuelCells,RWTHAachenUniversity,[email protected]

Summary.Alkalineelectrolysisreachingmorethan2A/cm2at2Visunusual.Usingpolymericmembranes(m-PBI)withliquidKOHelectrolyte,weachievepolarizationperformancesurpassingthoseofstate-of-the-artPEMreferencecells.

Abstract. We have employed potassium hydroxide doped poly(2,2’-(m-phenylene)-5,5’-bibenzimidazole) (m-PBI)membranesasseparatorsinalkalineelectrolysis.Thisclassofmembraneshaveshownhighionicconductivityin20-25wt%KOH.[1],[2]Themembranesreduceohmiclossescomparedtotraditionalporousseparatorsandenablehighcurrentdensitieswhencombinedwithactiveelectrodes.[3]

Theelectrodesuseaclassicperforatedplateelectrodegeometry.AvacuumplasmasprayedRaney-nickel-molybdenumcathode[4]andanuncoatednickelanodeisassembledinazero-gapconfigurationwithapre-dopedmembrane.Thisconfigurationallow forverygoodgas-liberationproperties,butmost likelydoesnot represent theoptimumuseofelectrodeandmembranearea.Nonetheless,weareabletoreachmorethan2A/cm2at2Vafter12hourbreak-in,seeFigure1.While themembranes show good chemical stability in up to 25wt% KOH, but have shown some increased in-celldegradation,theextendofthisisunknown.[5]Wedemonstratealifetimeofuptotwoweeksdependingonthickness.Cell failure is caused by membrane degradation, while performance decrease appear to be caused by electrodedegradation,whichwaspreviouslyshowntobestable.[6]

Figure6:Polarizationcurveofthecell:Raney-NiMocathode|m-PBI/KOHelectrolyte|Nickelanode.[KOH]=24wt%,T=80°C.

[1] D.Aili,K.Jankova,J.Han,N.J.Bjerrum,J.O.Jensen,Q.Li,Polymer.2016,84,304.[2] M.R.Kraglund,D.Aili,K.Jankova,E.Christensen,Q.Li,J.O.Jensen,J.Electrochem.Soc.2016,163,F3125.[3] M.Schalenbach,G.Tjarks,M.Carmo,W.Lueke,M.Müller,D.Stolten,J.Electrochem.Soc.2016,163,F3197.[4] G.Schiller,V.Borck,Int.J.HydrogenEnergy1992,17,261.[5] D.Aili,K.Jankova,Q.Li,N.J.Bjerrum,J.O.Jensen,J.Memb.Sci.2015,492,422.[6] G.Schiller,R.Henne,P.Mohr,V.Peinecke,Int.J.HydrogenEnergy1998,23,761.


82


COfromCO2–on-sitecarbonmonoxidegeneration

PeterBlennow,JeppeRass-Hansen,CasperHadsbjergandSørenPrimdahl

HaldorTopsoeA/S,HaldorTopsøesAllé1,DK-2800Kgs.Lyngby/[email protected]

Summary.AplantproducingpureCOfromasourceofCO2viasolidoxideelectrolysis.Theplantworkson-siteandiscost-competitive.

Abstract. This presentation will cover the technical and commercial features of Haldor Topsoe’s CO from CO2technology.HaldorTopsoe’seCOsisasolidoxideelectrolysiscell(SOEC)technologythatallowsthesafe,efficient,andcost-competitive production of carbonmonoxide directly at the site of facilitieswhere the gas is needed. The CO-generation device uses feedstock carbon dioxide and electrical power to produce CO in quantities ideal for mostoperationsthattodayrelyoncylinderortubetrailersupply.Themodularcontainerizeddesignallowsforacompactdesignandafootprintthatinmanycasesiscomparabletothetubetrailerloadingbay.

AneCOsplantisdeliveredasastand-aloneunitwithpower,CO2andproductgasconnections.Furthermore,theplantensureshighlevelsofpurity,producingCOat99.5%assaywithminimalcontaminantsandCO2asthemaincontaminant.AneCOssolutioncanalsobecustomizedtoproduceCOat99.999%purity.

OnsiteCOgenerationisasignificantdevelopmenttothemedical,pharmaceutical,metallurgy,electronicsandspecialtychemicalsindustries,whichrequirecarbonmonoxideintheirprocesses.TheeCOstechnologyensuresecurityofsupply,eliminatestheneedtotransporthazardousgas,anddrasticallyreducecostsrelatedtostorage,rentalsandconnections.Inthelongerrun,thistechnologyopensupforawholenewsegmentofgreenandsustainablechemicalsfromrenewablecarbonsources.


83

AbstractNo.61

ThermodynamicconstraintsinoperatingasolidoxideelectrolysisstackondrycarbondioxidegatheredfromtheMarsatmosphere.

JosephHartvigsena,JessicaElwella,S(Elango)Elangovana

aCeramatec,Inc.,SaltLakeCity,UT,[email protected]

Summary.ElectrolysisofdryCO2byhightemperatureelectrolysisencounterschallengesatbothextremesofthepO2rangeseenatthecathode.ThenickelcermetcathodecanbeoxidizedbypureCO2,whileCOproducedbyelectrolysiscanbefurtherelectrolyzedtocarbon.AvoidingelectrodeoxidationandcarbonformationbyCOreductionareessentialtosustainedoperationofMOXIEonMars.

Abstract.Ceramatechasdeveloped the solidoxideelectrolysis stack todemonstrateoxygenproduction fromMarsatmosphereCO2intheMOXIE1instrumentontheMars2020rover.Therearenoprocessutilitiessuchasair,hydrogen,nitrogen, or water available to MOXIE. MOXIE can only take in filtered Mars atmosphere, and in an unattendedoperation,produceoxygenfromtheCO2intheatmosphere.ThenickelcermetcathodeisoxidizedbypureCO2at800°Cwhichresultsinalossofconductivityandadisruptionofthemicrostructureduetovolumeexpansiononoxidation.

Mars atmosphere, which is about 96% CO2, is supplied to the solid oxide electrolysis stack by means of a scrollcompressor. The scroll pump is a fixed displacement device, so the delivered flow rate of CO2 will depend onatmosphericdensity,whichvariesasafunctionoflandingsiteelevationaswellasseasonalanddiurnalatmospherecycles.The landingsitehasnotyetbeenselected,butevenatagivensite thedensitywill varyoverawide range.Therefore,MOXIEmustbecapableofoperatingoverawiderangeoffeedstockrates.TheMOXIEsystemandoperatingstrategymustbedesignedtoprotectagainstcathodeoxidationandcarbondepositionastherearenoprovisionstorecoverfromeitherevent.

The thermodynamic and resulting electrochemical boundaries have beenmapped analytically and used to developsystemconfigurationsandoperatingstrategiestoprotectagainstcathodeoxidationandCOreductiontocarbon.Theseapproacheshavebeenandcontinuetobevalidatedexperimentallywithincreasingdegreesofsystemintegration.TheMOXIEstackprocessintegrationandoperationaldevelopmentpathandresultswillbepresented.

Acknowledgment: This material is based on work supported by NASA through JPL’s prime contract under JPLsubcontractnumber1515459. TheauthorswouldliketoacknowledgethecontributionsofMichaelHecht(MIT,MOXIEPrincipal Investigator, PI), JeffHoffman (MIT,MOXIEDeputyPI), JeffMellstrom (JPL,MOXIEProjectManager), CarlGuernsey(JPL,SOXEContractTechnicalManager),GeraldVoecks(JPL,SOXElead)insupportoftheCeramatecroleintheMOXIE.

1http://mars.nasa.gov/mars2020/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1683


84

AbstractNo.62

DevelopmentandflightqualificationofasolidoxideCO2electrolysisstackfortheMars2020MOXIEproject

JessicaElwella,JosephHartvigsena,S(Elango)Elangovana,DennisLarsena,TomMeadersa,LaurieClarka,EvanMitchella,ByronMilleta

aCeramatec,Inc.,SaltLakeCity,UT,[email protected]

Summary. The NASAMars2020missionwill land a Curiosity class rover onMars with a set of seven new scienceinstruments.2Oneoftheseinstruments,MOXIE,theMarsOxygenISRU(InSituResourceUtilization)Experiment,willdemonstrateoxygenproductionby solidoxideelectrolysisofMarsatmosphereCO2.CeramatechasdevelopedandqualifiedtheSolidOXideElectrolysis(SOXE)deviceforMOXIE.

Abstract.RenewedinterestinmannedexplorationofMarsisturningattentionbacktotheapplicationofsolidoxideelectrolysisforproductionofoxygenfromCO2.TheMartianatmosphereis96%CO2,makingitavaluableresourceforextractionofoxygenforlifesupport.Anevengreateroxygenrequirementisforascentvehiclepropellantenablingareturntoearth.ThefundamentaloperatingprinciplesandmaterialsoftheMarsISRUapplicationarenodifferentthanfor themorecommonterrestrialhydrogenand synfuelapplications.However, theenvironments thedevicewillbesubjectedtoinreachingMars,andwhileoperatingontheMartiansurface,createtheneedforsomeuniqueandhighlyrigorousqualificationtesting.

Thethermalandmechanicalenvironmentrequirements imposedonMOXIEareextreme.MOXIEmustdemonstratethat itcanreachMars intact.Thisqualificationeffort includessubjectingthestackandthermal insulationsystemtomulti-axisshockandvibrationtosimulatetheloadsoflaunch,entry,descentandlanding.Sincethestackwilloperatewithanominal1barinternalpressureagainstaMarsambientpressurethatvariesaround10mbar,sealsarecritical.Thestackisheldincompressiontocounteracttheinternalpressure,aswellastosecureitwithinthethermalinsulationpackage,requiringthedemonstrationofthemechanicalloadcapabilityofthestack.

Theroverisenergylimited,andMOXIEwillrequirenearlythefullSol’s(Marsday)energybudgetfora2-4houroperatingcycle.Itmaybeweeksbetweenoperatingcycleswhileotherexperimentsarebeingconducted.Asaresult,thesystemwillbeexposedtoextremesofcoldbetweenoperationalcycles.

Ceramatec stackshas successfullymetoperating targets foroxygenproductionandoxygenpurityafterundergoingmechanicalcompression,shockandvibration,coldcyclingtoaslowas-65°C,andthroughover20thermal/operatingcycles.TheMOXIEstackdevelopmentandqualificationprocesshistorywillbepresented.

Acknowledgment: This material is based on work supported by NASA through JPL’s prime contract under JPLsubcontractnumber1515459. TheauthorswouldliketoacknowledgethecontributionsofMichaelHecht(MIT,MOXIEPrincipal Investigator, PI), JeffHoffman (MIT,MOXIEDeputyPI), JeffMellstrom (JPL,MOXIEProjectManager), CarlGuernsey(JPL,SOXEContractTechnicalManager),GeraldVoecks(JPL,SOXElead)insupportoftheCeramatecroleintheMOXIE.

2http://mars.nasa.gov/mars2020/mission/instruments/


85

AbstractNo.63

SyntheticmethaneproductionfromCO2methanation:processintegrationwithSOECelectrolyserandreactionkineticsonhydrotalcite-derivedcatalystand

PaoloMaroccoa,AlexandruEduardMorosanub,AndreaLanzinia,DomenicoFerreroa,EmanueleGigliob,SamirBensaidb,MassimoSantarellia

aDepartmentofEnergy,PolitecnicodiTorino,Torino(ITALY)bDepartmentofAppliedScienceandTechnology,PolitecnicodiTorino,Torino(ITALY)

[email protected]

Summary.RecyclingwasteCO2withelectrolyticH2toproducesyntheticfuelsisapromisingsolutiontoreducetheuseoffossilfuels.Wepresentexperimentsandthereactionkineticsequationforahydrotalcite-derivedNicatalystusedforCO2methanation.Themethanationreactors’designandprocessintegrationwiththeSOECisalsoprovided.

Abstract.ThisworkanalysestheenergyperformanceandreactorengineeringaspectsoftheintegrationofanSOECwith a downstreammethanation section,which comprises a series of two inter-condensed reactors. Theproposedconfigurationisabletoproduceanoutletsyn-gaswith95mol.%ofCH4.OneofthemainchallengesisrepresentedbythereactorthermalmanagementbecauseCO2hydrogenationisastronglyexothermicreactionandmayleadtoahotspot(andthustocatalystthermaldegradation),especiallywithinthefirstreactor.Toavoidtheriskofoverheating,partof carbondioxidebypasses the first reactor to feeddirectly the secondone.The steamproduced fromthe reactorcoolingsystemcanbeusedasareactantinthesolidoxideelectrolyser(SOEC).SuchstrongthermalintegrationamongthemethanationsectionandtheSOECleadtoahigherefficiencythanobtainedthroughpower-to-gassystemsbasedonconventional low-temperatureelectrolysis.Amicro-reactorconfigurationhasbeenusedtoevaluatethecatalyticactivity of a hydrotalcite-derived Ni catalyst for CO2 methanation. Experiments have carried out at differenttemperatures(withintherange270-390°C),H2/CO2feedratiosandflowrates.Theimpactofthereactionproductsonthereactionratehasbeenalsoevaluatedbyco-feedingreactantswithH2OandCH4.Differentkineticmodelshavebeenevaluatedstartingfromexperimentalresults.Powerlaw,powerlawwiththeinhibitioninfluenceofadsorbedwaterorhydroxyl, and finally a Langmuir-Hinshelwood (LH) approach have been compared. The overall process was firstmodelledbyconsideringtheSabatierreaction.Then,thereversewater-gasshift(RWGS)reactionwasalsoaddedtothesimulation to take intoaccount thepresenceofCO.Anonlinear regressionanalysiswasperformedtoevaluate thekineticparameters.ResultsshowabetterfittingofexperimentaldatausingtheLHandthepowerlawwiththeinhibitiontermapproaches.Thereactionkineticsequationhasbeenthenusedin1Dplugflowmodelthatsimulatesthethermalandchemicalperformanceofanevaporatingwater-cooledmulti-tubularmethanationreactor.

(Left)ParityplotconsideringapowerlawwiththehydroxylinhibitiontermforboththemethanationandtheRWGSreactions.

(Right)IntegratedSOECmethanationplant.


86

AbstractNo.64

Performanceanddurabilityoffour6-cellsolidoxideelectrolyserstacksforhydrogenandsyngasproduction

MikkoKotisaaria,OlivierThomanna,DarioMontinarobandOlliHimanenaaVTTTechnicalResearchCentreofFinlandLtd.,FuelCells,Biologinkuja5,FI-02150Espoo,Finland

bSOLIDPowerSpA,VialeTrento115/117,38017Mezzolombardo,Trento,Italy

[email protected]

Summary.Performanceanddurabilityof fourSOEstacksoperatedwithdifferentgascompositionsand indifferenttemperatureswas analysed in order to estimate their suitability for fuel synthesiswith co-electrolysis powered byintermittentelectricitysupply.

Abstract.The6-cellstackprototypeswereproducedbySOLIDPower.Theoperationtemperaturerangewas700-800°CandtheCO2fractioninthecathodeinlet0.00-0.45,representativeofcasesinwhichtheelectrolyserwouldbecombinedwith a fuel synthesis process andproducehydrocarbonswith different hydrogen-to-carbon ratios. CharacterizationmethodswereiVcurves,loadcyclingandgaschromatographyofthecathodeoutletgas.Theperformanceofallstackswasfoundtodependprimarilyontheoperationtemperatureandonlytoasmallextentontheinletgascomposition.Gas analysis of the cathode outlet indicated that the measured compositions were in line with the compositionscalculatedfromthermodynamicalequilibrium.Thisindicatesthatthewatergasshiftreactionwasatequilibriuminthetestedrange.

Moreover,durabilitytestswereperformedat750°Cinsteamelectrolysisandco-electrolysisconditions,testhoursofallthestacksreachingcumulatively5800h.Thedegradationresultsarediverse.Severalperiodsofvoltagedecreasewererecorded,thelongestbeing1500hsteamelectrolysiswithavoltagedecreaseof9mV/kh.Thereasonbehindthedecreasingvoltage,theapparentactivation,isnotclearlyunderstood.Althoughcomplex,theresultsareencouragingand indicate that this type of stack is a suitable candidate for co-electrolysis operation for hydrogen and syngasproduction.

ThisresearchhasreceivedfundingfromtheEuropeanUnion'sSeventhFrameworkProgramme(FP7/2007-2013)fortheFuel Cells andHydrogen Joint Technology Initiativeunder grant agreementNo621173and fromEuropeanUnion’sHorizon2020ResearchandInnovationProgrammeundergrantagreementNo731224.


87


EffectofcatalystloadingonperformanceanddurabilityofaPEMwaterelectrolysiscellbasedonanAquivion®perfluorosulfonicacid(PFSA)membrane

AntoninoSalvatoreAricòa,StefaniaSiracusanoa,VincenzoBaglioa,NicholasVanDijkbandLucaMerlocaCNR-ITAE,ViaSalitaS.LuciasopraContesse5,98126Messina,Italy

bITMPower(Research)Ltd,UnitH,SheffieldAirportBusinessPark,EuropaLink,SheffieldS91XU,UKcSolvaySpecialtyPolymersItalySpA,vialeLombardia,20,20021Bollate,Italy

[email protected]

Summary.

Abstract.Oneofthemainproblemsthatafutureenergysystemmustaddressistheexcessofrenewableenergywhichcannotbetransferredtothegridwhendemandislowandthusmustbecurtailedbythegridoperators.Thisproblemcanbeconvenientlyaddressedbyconvertingtheintermittentsurplusofelectricalenergyintohydrogenandstoringtheenergy chemically. Electrolysis of water using renewable energy sources is one of the most promising chemicalprocessestoproduce‘‘green”hydrogeneconomicallywiththehighpurityneededforfuelcellbasedelectricvehicles.Membrane-electrodeassemblies(MEAs)designedforpolymerelectrolytemembrane(PEM)waterelectrolysis,basedonAquivion®,perfluorosulfonicacid(PFSA)membrane,withvariouscathodeandanodenoblemetal loadings,wereinvestigatedintermsofbothperformanceanddurability.UtilizingananosizedIr-Ruoxidesolidsolutionanodecatalystand a supported Pt/C cathode catalyst, in combination with the Aquivion® membrane, gave excellent electrolysisperformancesexceeding3.2A·cm-2at1.8Vterminalcellvoltage(~80%efficiency)at90°Cinthepresenceofatotalcatalystloadingof1.6mg·cm-2.Averysmalllossofefficiency,correspondingto30mVvoltageincrease,wasrecordedat3A·cm-2usingatotalnoblemetalcatalystloadingoflessthan0.5mg·cm-2.Steady-statedurabilitytests,carriedoutfor >3000h at 3A·cm-2, showedexcellent stability for theMEAwith lownoblemetal catalyst loading (cell voltageincrease~5-10μV/h). Thereforeoperationat veryhigh currentdensities ispossible in thepresenceof lowcatalystloadingandareductionofcapitalcostsmaybeachievedwithoutcompromisingsignificantlythestackdurability[1].

Acknowledgment

TheresearchleadingtotheseresultshasreceivedfundingfromtheEuropeanCommunity’sH2020Programme.WorkperformedwassupportedbytheFuelCellsandHydrogenJointUndertakinginthecontextofprojectHPEM2GASG.A.700008.

Reference

[1]S.Siracusano,V.Baglio,N.VanDijk,L.Merlo,A.S.Aricò,ApplEnergy(2016),http://dx.doi.org/10.1016/j.apenergy.2016.09.011


88

AbstractNo.66

AgingofPEMWEcatalystcoatedmembranesduringdynamicoperation:Electrochemicalandmicroscopicstudy

GeorgiosPapakonstantinoua,ElenaWillingerb,TanjaVidakovic-Kocha,RobertSchlöglb,c,KaiSundmachera,daMaxPlanckInstituteforDynamicsofComplexTechnicalSystems,ProcessSystemsEngineering,Magdeburg,

GermanybDepartmentofInorganicChemistry,Fritz-HaberInstituteofMaxPlanckSociety,Berlin,Germany

cMaxPlanckInstituteforChemicalEnergyConversion,Mülheima.d.Ruhr,GermanydOtto-von-GuerickeUniversityMagdeburg,DepartmentProcessSystemsEngineering,Magdeburg,Germany

[email protected]

Summary.Thedynamicoperation,mimickingfluctuatingpower,ofPEMWEsinglecell, inducedsignificantstructuralandmorphological alterationsof the amorphous Ir hydroxide containing anode catalyst layerwithout affecting theelectrochemicalresponse.TheobservedeffectsquestiontheuseoflowIrloadingsundertechnicalconditions.

Abstract.Theenvironmentalimpactoffossilfuelsusageispushingtheinteresttowardssustainableenergysystems.The increasing shareof renewableelectricity requires thedevelopmentof technologies able to store theexcessiveenergyproducedduringtheoff-peakdemandperiods,i.e.duringthenightorweekend.H2OelectrolysisisasuitabletechnologywithhighthermodynamicefficiencyforH2productionandcanbeusedtoat least temporarilystorethesurplusenergy in the chemicalenergyofH2.Among theknownH2Oelectrolysisprocesses, thepolymerelectrolytemembrane(PEM)H2Oelectrolysis isparticularlyattractivebecauseitcancopewiththeintermittentandfluctuatingnature of renewable electricity. However, the harsh oxidative and corrosive environment (low pH and highelectrochemicalpotential)necessitatestheuseofexpensivecorrosionresistantmaterialsintheanode,suchasnoblemetals as catalysts and Ti based current collectors and separator plates. Additionally, the sluggish anode reactionkinetics,evenwiththecurrentlystate-of-the-artIrbasedcatalystsintermsofbothactivityandstability,requirehighloadingsincreasingsignificantlythecost,especiallyinviewofthescarcityofIrinearth’scrust.Therefore,thesystemdurabilityisofessentialinterest,sinceextendedlifetimecanpartiallycompensateforthehighcost.

HYDRioncatalystcoatedmembrane(CCM)ofcirculargeometry(63.5cm2activearea),consistedofIrbasedanode,PtbasedcathodeandN117membrane,wasplacedincommercialTibasedPEMWEsinglecell(Sylatech).PorousTilayer(PTL,1mmthickness,80%porosity),madeofsinteredTifibres,intheanodeandhydrophobisedcarbonpaper(H2315I6,Freudenberg,210μmthickness)inthecathodewereservingascurrentcollectorsanddiffusionmedia.Tigrid(Dexter,1 mm thickness) was used as spacer in the anode instead of flow channels to facilitate the reactants/productsdistribution.Theeffectofdynamicoperation,consistingoframp(100mV/s)/hold(2.5minand15min)between1.4and 1.8 V at 60 oC and ambient pressure, applied for ca. 750 h, on the cell performancewas examined by in-situelectrochemicaldiagnostictechniques,suchaspolarisationsimultaneouslywithimpedancemeasurementsandcyclicvoltammetry(CV).Themicrostructuralalterationsinducedbytheexperimentalprotocolwereidentifiedbypost-testmicroscopic investigations, including scanning and scanning transmission electronmicroscopies, complemented byelectrondiffractionandx-rayphotoelectronspectroscopies.

Thecellperformanceattechnicalcurrentdensitieswasheavilydictatedbytheoxygenevolutionreaction(OER)kineticsandhighohmicresistance,with50%shareat1A/cm2and60oC.Itwasestimatedthatca.50%oftheohmicresistancecanbeassignedtotheanodecatalystlayer(ACL)resistanceandthecontactresistancebetweentheACLandTiPTL,signifyingtheimportanceofthecatalystconductivityandtheACL-TiPTLinterface.Thecellperformancewasenhancedduringthefirst100hoftestingandthereafterwasdecliningwithaveragedegradationrateofca.30μV/hat0.75A/cm2.Bothperformancevariationsweremajorlydictatedbytheohmicresistancevariation,providingiRfreedegradationratelowerthan10μV/h.CVindicatednosignificantalterationsoftheapparentelectrochemicalactivesurface,contradictingthestrongstructuralandmorphologicalalterationsevidencedbypost-testanalysis.ThelatterrevealedIrdissolutionwith formationofa sparseband inside themembraneandclose to themembrane-ACL interfacewith Ir containingparticles,IrmasslossfromthebackoftheACLandrespectiveconcentrationatthemembrane-ACLinterfaceforminglargeagglomerates,andformationofrutiletypeplateletswellembeddedwithintheoriginallypresentamorphousIrhydroxidecatalystphase.


89

AbstractNo.67

DurabilityofPEMECMEAs

LailaGrahl-Madsena,MadeleineOdgaarda,MustafaHakanYildirima,JensOlufJensenb,LarsNilausenCleemannbandQingfengLib

aEWIIFuelCellsA/S,EmilNeckelmannsVej15A,DK-5220OdenseSE,DenmarkbDTUEnergy,DTULyngbyCampus,Kemitorvet,Building207,2800Kgs.Lyngby,Denmark

e-mailofcorrespondingauthor:[email protected]

OneofthemainchallengesforamorewidespreadutilisationofPEMelectrolysisisrelatedtothepresenthighcostofparticulartheflow-fieldplates(machinedtitaniumplates)andtheelectrodesthatareequippedwithahighnoblemetalcatalystloading.Thestate-of-the-artcatalystcostofthePEMECMEAis»10%ofthetotalstackcost3.However,particulartheOERcatalyst(iridium-oxide)drawinanimportantR&Deffortasiridiumdefinesalimitedresourcebeingtherarestelementontheearthcrust.Consequentlywillanincreasinguseofiridiumpossessesapotentialfuturecostissue.TheR&Deffortsarerelatedtowardsnovelcatalystse.g. Ir-Ru-oxides and/or lower catalyst loadings. The state-of-the-art PEM electrolysisMEA do possess adurablelonglifetimepotential(Fig.1),butthismaybealteredforlowcatalystloadedMEAs.Presentedislong-timesinglecelldurabilitydataofPEMelectrolysisMEAsequippedwithdifferentcatalystsandvariatedcatalystloadings.Microstructuralpost-mortemcharacterisationhasbeenperformedonselectedMEAs.TheinfluenceoflowcatalystloadingsandalternativeOERcatalystsonthedurabilityisdiscussed.

Fig.1‘Steadystate’operationalhoursversusthecalculatedlifetime.

3Bertuccioli,L;Chan,A;Hart,D;Lehner,F;Madden,B&Standen,E(2014):DevelopmentofWaterElectrolysisintheEuropeanUnion.Finalreport.Availableon-lineathttp://www.fch-ju.eu/sites/default/files/study%20electrolyser_0-Logos_0.pdf

100

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EoLcriteria:U-Cell=2V

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90

AbstractNo.68

TowardsselectivetestprotocolsforacceleratedinsitudegradationofPEMelectrolysiscellcomponents

ThomasLickerta,ClaudiaSchwarza,PatriciaGesea,ArneFallischa,MalteSchlütera,NicolasHöflingaandTomSmolinkaaaFraunhoferInstitutforSolarEnergySystems,Heidenhofstr.2,79110Freiburg,Germany


Summary.Timeandcostconsumingtestsfordegradationanalysismaketheaccelerationofthesenecessary.Currently,suchacceleratedtestprotocolsarenotinexistenceinthefieldofelectrolysis.Herein,wepresentthefirststeptowardsselectiveinsitudegradationtestsofdifferentcomponentsofaPEMelectrolysiscell.

Abstract. The understanding of degradation effects within polymer electrolyte membrane water electrolysis cells(PEMWE) is an important issue for life timeprediction and component development for commercial PEMWE stackmanufacturers.Sincelife-timetestsaretimeandcostconsuming,acceleratedstresstests(AST)arerequiredtogainthesame amount of information within a fraction of time. In a first step, the development of testing procedures fordegradationstudiesofindividualcomponentsisaddressedtobeabletodistinguishbetweentheinfluencesoriginatingfromdifferentparametersduringoperation.Inotherwords,whatisdegradingthemembrane,thecatalystlayers,thetitaniumcomponentsandhow.Forexample,whencoupling renewableswithaPEMelectrolyser, likewindorsolarsystems,fluctuatingpowerisusual.Thesefluctuationsareundersuspiciontodegradethecatalystlayermorethanthemembrane.

Inasecondstep,theaccelerationoftheunderlyingprocesseswillbe investigated. Inthiscontribution,theworkonselectivedegradationtestingprotocolswillbepresented.Differentcurrent/voltageprofilesweretested ina25cm2laboratorytestcellwithAucoatedflowchannels,commercialmembraneelectrodeassemblies(MEA)andAureferenceelectrodes for separation of anodic and cathodic contributions to the voltage decay. Electrochemical impedancespectroscopy (EIS) (see Figure 2) and steady-state polarisation curves (see Figure 1) were used for in situcharacterisation. Scanning electronmicroscopy (SEM) and an in-house developed testmeasurement for interfacialcontact resistances (ICR)wereemployedasex situcharacterisation to investigatemembrane thinningand titaniumoxideformation.

Figure7:Polarisationcurves(+IR-correction)atVariouspointsintimeduringtheAST

Figure8:Impedancespectraat1A/cm²and2A/cm²atvariouspointsintimeduringtheAST

0.0 0.5 1.0 1.5 2.0 2.5 3.0

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filled dots @ 1 A/cm²

unfilled dots @ 2 A/cm²


91

AbstractNo.69

MechanicalcharacterisationanddurabilityofsinteredbodiesforPEMelectrolysis

ElenaBorgardta,OlhaPanchenkoa,MartinBramb,MartinMüllera,DetlefStoltena,candWernerLehnerta,caInstituteofEnergyandClimateResearch

ElectrochemicalProcessEngineering(IEK-3),ForschungszentrumJülichGmbHbInstituteofEnergyandClimateResearch

MaterialsSynthesisandProcessing(IEK-1),ForschungszentrumJülichGmbHcFacultyofMechanicalEngineering,RWTHAachenUniversity,AachenGermany

[email protected]

Summary.Indifferentialpressureelectrolysis,themechanicaldurabilityofcurrentcollectorsmustbeensured.Inordertowithstandrecurringdifferentialpressure,ahighplasticityofthetitaniumbodyiscrucial.Itwasstudiedhowplasticitycanbeinfluencedbyvaryingsinteringtemperatureandbypossiblecontaminationofthematerial.

Abstract.Differentialpressureelectrolysisoffersthepotentialforincreasingtheefficiencyofcompressionofhydrogenfromelectrolysis.Duetothedifferentialpressureactingwithinthecell,theanode-sidecurrentcollectorissubjectedtohighstresses. If themechanical strengthof thecurrentcollector isnot sufficientand thus thecomponent fails, thecatalyst-coatedmembrane(CCM)isnolongerstabilized.ThusfailureofthesinteredbodyleadstoafailureoftheCCMand finally to failure of the hole cell. For safety reasons, themechanical stability of the current collectormust beensured.CurrentcollectorsforPEMelectrolysisaretypicallypreparedbythermalsinteringoftitaniumpowder.Theseporous titanium transport layers ensure a good electron conductivity and corrosion resistance [1]. Themechanicalpropertiesofpuretitaniumaresignificantlyinfluencedbyevenasmallamountofimpurities.Inparticular,theamountofoxygen,nitrogenandcarbonledtobrittlenessandloweredductility[2].

Themechanicalanddynamicmechanicalbehaviourofsinteredtitaniumsheetshavebeeninvestigatedviastress-straincurvesandperiodicloadsintestcell,respectively.Experimentswerecarriedoutwithsamplesofpowderswhichdifferinshapeand in theirchemicalcomposition.Sampleswithsintering temperatures in the rangeof800-1200°Cwereavailable foreachpowder.Samplesmadeof sphericalpowderwere inaporosity rangeof33-10%andsamplesofshapelesspowderinarangeof55-10%.

Inthestress-straindiagrams,itwasfoundthathighersinteringtemperatureandlowerporositywereassociatedwithhigher tensile strength and higher deformability. It was noticeable that samples from spherical powders had aconsiderableincreaseintheductilityfromasinteringtemperatureof1000°Conwards,whereassamplesfromshapelesspowdersshowednogreatincreaseinductilityatelevatedsinteringtemperature.Thematerialsexhibitingthegreatestplasticdeformabilitywereabletowithstandthegreatestdifferentialpressureinthetestcell.Alsoithasbeenshowninthedurabilitytestthatsampleswithalowsinteringtemperaturecannotguaranteesufficientfatiguestrength.

Noneofthesampleswithporosityabove25%showedsufficientmechanicalstabilityforaflowfieldwidthof4mm.Ahighporosityaswellashighstaticanddynamicstrengthforaflowfieldwidthof3mmcouldonlybedemonstratedbyoneofthesamplestestedhere.However,thereisariskthatimpurities,whichenterduringthesinteringprocess,leadtoembrittlementandthustothefailureofthecurrentcollector.

1. Carmo,M.,etal.,AcomprehensivereviewonPEMwaterelectrolysis.Internationaljournalofhydrogenenergy,2013.38(12):p.4901-4934.

2. Zwicker,U.,TitanundTitanlegierungen,inReineundangewandteMetallkundeinEinzeldarstellungen.1974,SpringerVerlag:Berlin.p.219.


92

AbstractNo.70

Complexofcobaltandmolybdenumcarbidenanoparticlesforefficientoxygenevolutionreactioninalkalineelectrolytes

MinJoongKima,SunghyunKimb,DongHoonSonga,SeKwonOha,KeeJooChangb,andEunAeChoa*aDepartmentofMaterialsScienceandEngineering,KoreaAdvancedInstituteofScienceandTechnology

bDepartmentofPhysics,[email protected]

Summary.WereportacomplexofCoandMo2CnanoparticlesasanefficientelectrocatalystforalkalineOER.ChemicalcouplingofCowithMo2C leadsto increase inOH

-affinityandoxygenbindingenergyonCosurface.ThesechangessignificantlydiminishkineticbarrierforOERonCosurface,resultinginhighOERactivityinalkalineelectrolytes.

Abstract.Increasingdemandforcleanenergyhavetriggeredresearchesonalternativeenergysourcesanddevicestoreduceuseoffossilfuel.Hydrogenhasbeenconsideredasoneofthemostpromisingenergysourceforfutureduetoitshighenergydensityandnoairpollutantemission.Splittingwaterintohydrogenandoxygenisanenvironmentallyfriendlymethodforproducinghydrogengas.Thistechnologycanstoreexcesselectricenergyintheformofchemicalbondofhydrogen,whichcanresolveanissueaboutsurpluselectricpowerofpresentrenewableenergysystemscausedbyirregularenergysourcesuchasairflowandsunlight.

Waterelectrolysisreactionisdividedintotwohalfreactions;hydrogenevolutionreaction(HER)andoxygenevolutionreaction(OER).HighoverpotentialsofbothHERandOERarethemostsignificantproblemstohamperreactionrateandoverall efficiencyofwaterelectrolysis, especiallyOERhasmuchhigheroverpotential thanHER.Therefore, recentlymajoreffortshavebeendevotedtoexploringactivecatalystsfortheOERinwaterelectrolysiscell.

Herein,wereportnovelcatalysts,whichcomposedofCoandmolybdenumcarbide(Mo2C)nanoparticles(Co-Mo2C),asefficientOERcatalystsforalkalinewaterelectrolysisMo2Chasverysimilarelectronicstructurewithplatinum(Pt)groupmetal. Therefore, it can be expected that Co-Mo2C can have highOER activity in alkaline electrolytes by chemicalcouplingeffectoftwomaterials(Co,Mo2C)attheirinterfaces.WesynthesizedCo-Mo2Cbyusingasimplesolutionbasedprocess. g-C3N4 was used as a carbon source for carburizing reaction of Mo. The synthesized Co-Mo2C exhibitedenhancedactivitycomparedwithCoandRuO2catalystsinalkalineelectrolytes(0.1and1MKOH).From,XPSandDFTcalculationresults,highOERactivityisascribedtoincreaseinOH-affinityandoxygenbindingenergyonCosurfacebychemicalcouplingofCoandMo2C.Moreover,wetriedtoadditionallymodifytheelectronicstructureofCo-Mo2Cbyincorporating other transition metals into Co, such as iron (Fe), manganese (Mn), nickel (Ni). Fe-doped Co-Mo2CexhibitedhigheractivityforOERcomparedthanCo-Mo2Candrutheniumdioxide(RuO2)catalystsinalkalinemedia(0.1and1MKOH).But,othertransitionmetal-dopedCo-Mo2ChavelowerOERactivitythanundopedmaterials.


93

AbstractNo.71

Gold-MetalOxideCore-ShellNanoparticlesAsElectrocatalystsforWaterOxidation

AlainaStricklera,MariaEscudero-Escribanoa,bandThomasF.JaramilloaaStanfordUniversity,DepartmentofChemicalEngineering,443ViaOrtega,94305Stanford,California

bUniversityofCopenhagen,DepartmentofChemistry,Universitetsparken5,2100Copenhagen,[email protected]

Summary.Wepresentthesynthesis,characterisationandelectrochemicalperformanceofAu-coremetaloxide-shell(Au@MxOywhereM=Ni,Co,Fe,andCoFe)catalystswithenhancedactivityfortheoxygenevolutionreactioninalkalineelectrolyte.

Abstract.Water oxidation, or the oxygen evolution reaction (OER), is a key half reaction ofmany electrochemicalprocesses for sustainable energy conversion and storage technologies such aswater splitting, reduction of carbondioxideandmetal-airbatteries.Renewableenergycanbeconvertedintohighpurityhydrogenbyelectrochemicalwatersplitting.ThemainproblemofwaterelectrolysersistheslowkineticsoftheOER.Althoughtransitionmetaloxideshaveshown high OER activity and stability in alkalinemedia [1], high overpotentials are still required. Au supports canenhancetheOERactivityformanytransitionmetaloxidesinalkalinemedia[2,3].

Herein,wepresentthechemicalsynthesis,characterisationandperformanceofAu-coremetaloxide-shell(Au@MxOywhere M=Ni, Co, Fe, and CoFe) catalysts for the OER. Particle morphology and composition were analysed bytransmissionelectronmicroscopy(TEM),scanningTEMenergydispersivespectroscopy(STEM-EDS),scanningelectronmicroscopy(SEM),andx-rayphotoelectronspectroscopy(XPS).ElectrochemicalactivityandstabilitywereevaluatedinathreeelectroderotatingdiskarrangementinFe-freeconditionsfornon-Febasedcatalysts.AllAu@MxOycore-shellnanoparticlesdemonstratedenhancedactivitywithAu[4].OurresultsdemonstratethattheAu-coretransitionmetalalloyoxide-shellstructureisapromisingstrategytoachievehighperformanceOERcatalysts.

[1]Burkeetal.,Chem.Mat.2015,27,7549.

[2]Gorlinetal.,J.Am.Chem.Soc.2014,13,4920.

[3]Ngetal.,NatureEnergy2016,1,16053.

[4]Strickler,Escudero-Escribano,Jaramillo,tobesubmitted,2017.


94

AbstractNo.72

Modifiedcarbonnanomaterialsashighlyactiveelectrocatalystsforwater-splittingMohammadTavakkolia,TanjaKallioa,EskoI.Kauppinenb,andKariLaasonena

aDepartmentofChemistry,SchoolofChemicalTechnology,AaltoUniversity,P.O.Box16100,FI-00076,Espoo,FinlandbDepartmentofAppliedPhysics,SchoolofScience,AaltoUniversity,P.O.Box15100,FI00076,Espoo,Finland

[email protected]

Summary.Herein,theprocessofsynthesisofcarbonnanotubes(CNTs)ismodifiedtogrowcarbon-encapsulatedironnanoparticlesasefficientcatalystsforhydrogenevolutionreaction(HER)inacidicmedia.Then,asimpleelectrochemicalmodificationisappliedtomakethesecatalystmaterialsactiveforoxygenevolutionreaction(OER)inalkalinemedia.

Abstract.

Electrochemicalwatersplittingcanbedividedintotwohalfreactions:thehydrogenevolutionreaction(HER)andtheoxygenevolutionreaction(OER).ForHER,efficientandstablenon-preciouscatalystsarerequired.Furthermore,theefficiencyofwaterelectrolysisisseverelylimitedbythelargeanodicoverpotentialandsluggishreactionrateofOER.Therefore,thedevelopmentofefficientelectrocatalystsforOERhasalsodrawnmuchattention.

ForHER, single-shell carbon-encapsulated ironnanoparticles (SCEINs)decoratedonsingle-walledcarbonnanotubes(SWNTs)haveshownultra-highactivityandstability forHER inacidicmedia,comparable to thatofplatinumbasedelectrocatalysts(Figure1a)[1].TheSCEIN/SWNTsampleissynthesizedbyanovelfastandlowcostaerosolchemicalvapordepositionmethodinaone-stepsynthesis[1].InSCEINs,thesinglecarbonlayerdoesnotpreventdesiredaccessof the reactants to the vicinity of the iron nanoparticle but protects the active metallic core from oxidation anddissolutioninacidicmedia.

ForOER,asacriticalreactioninelectrochemicalwatersplittingandrechargeablemetal–airbatteries,thestructureofcarbon-encapsulated iron nanoparticles (CEINs) decorated on carbon nanotubes (CNTs) is changed to high qualitycrystalline maghemite (γ-Fe2O3) nanoparticles decorated on CNTs (γ-Fe2O3/CNT) through a simple electrochemicalmethod(Figure1b)[2].Theγ-Fe2O3/CNTsampleisreportedasahighlyactiveanddurablecatalyticmaterialforOERinalkalinemedia[2].

Figure1.a,SchematicrepresentationoftheSCEIN/SWNTsampleandHERontheSCEINs.b,SchematicrepresentationfortransformationofCEIN/CNTtoγ-Fe2O3/CNTasanactiveelectrocatalystforOER.

REFERENCES

[1]M.Tavakkoli,etal.,Angew.Chem.Int.Ed.,54,2015,4535–4538.

[2]M.Tavakkoli,etal.,J.Mater.Chem.A,4,2016,5216-5222.

a) b)


95

AbstractNo.101

Influenceofgeometryandkineticofhydrogenandoxygenevolutiononthecurrentdensitydistributionandelectrodepotentialsinbipolarelectrolyzers.

AlejandroN.Collia,HeronVrubela,ErnestBurkhalterbandHubertH.GiraultaaLaboratoired’ElectrochimiePhysiqueetAnalytique,EcolePolytechniqueFédéraledeLausanne

Ruedel'Industrie17,CH-1951Sion,Valais/Switzerland,Tel.:+41216933143bEXENSàrl

RuedelaCombe1,CH-1196Cland,Vaud/Switzerland,Tel.:[email protected]

Summary.Thesecondarycurrentdistributioninanelectrolizerwithbipolarelectrodeswastheoreticallydeterminedbymeansofanownalgorithmthatallowsperformingthepotentialdistributionfromafixedappliedcurrent.Analysisofcurrent and potential distribution were performed taking into account kinetics of oxygen and hydrogen and cellgeometryfromindustrialconditions.Mainsfiguresofmeritwereevaluated.

Abstract.Thebipolarelectrolyzerconsistofaseriesofidenticalcells.Eachcellisintheformofaverticalchannelofacircularorrectangularcrosssection.Themajorattractionsofthebipolarreactorareeasyconstruction,savinginspacethatacompactdesignallows,andthelowercostoftheelectricalequipment.Themaindisadvantageofthereactoristhepresenceofparasiticelectricalcurrents(bypass)atthelowerandupperpartsoftheelectrodestack.Thisresultsinanelectricalefficiencyloss,anon-uniformpotentialandcurrentdistributionandconsequently,anincreaseinpossiblecorrosionratesofelectrodes.Bypasscurrentscanbereducedbyincreasingtheelectricalresistanceofthechannelsandmanifold,butatthesametime,increasingtheoverallelectrolyticpowercostduetoincreasingcellresistance.

Inthepast,manyauthorshaveinvestigatedinasimplifiedwaycurrentdistributioninbipolarreactorsusingelectricalanalogy [1]orbysolvingLaplaceequationandassuminganodicandcathodicoverpotentials [2]or imposinga fixedpotential(independentofkinetics)inbipolarelectrodes[3].Fromexperimentaldataitwasshownthatsimplifiedmodelsarenotaccurateduetonon-linearcellcurrent-voltagesresultsareobtainedwhenconductivityofelectrolyteishighenough,asinalkalineelectrolyzers(80°Cand30%KOH),anditisduetothefactthattheelectricfieldinsidethereactorisnotsufficienthightopolarizecompletelybipolarelectrodes[4].

Theobjectiveofthiscommunicationistoconductasimulationstudyoftheelectrochemicalprocessesinvolveinthiskindofsystemsfromrealkineticdata,togaininsightsintothepresenceofbypasscurrentsexistinginbipolaralkalineelectrolysers,andtoprovidesuggestionsthataidindesignconsiderations.KineticsparameterwereobtainedforNickelandNickelRaneyat25and80°CinKOH6MassupportingelectrolyteusingAg/AgClasreferenceelectrode.

Inthemathematicalmodelsomeassumptionsaremade:Themetalphaseintheelectrodesisisopotential;theeffectofgasesgeneratedattheelectrodesontheelectrolyteresistivitycanbedisregarded.Theeffectofkineticparametersonpotentialandcurrentdistributionofterminalandbipolarelectrodeswereanalysed,alsomolarenergyconsumptionand overall electrolytic power costwere evaluated for different geometries and, as consequence, bypass currents.Showing thatwhen leakagecurrent increase,also cellpotentialdecreases.Helping to reach, In thecaseof catalystresistant to corrosion, a lower overall electrolytic power cost and in some cases a slightly lower molar energyconsumption.

References.[1]I.Rousar,CalculationofCurrentDensityDistributionandTerminalVoltageforBipolarElectrolyzers;ApplicationtoChlorateCells,JournaloftheElectrochemicalSociety116(1969)676.[2]I.Rousar,J.Thonstad,Calculationofbypasscurrentsinmoltensaltbipolarcells,JournalofAppliedElectrochemistry24(1994)1124.[3]E.R.Henquín,J.M.Bisang,Effectofleakagecurrentsonthesecondarycurrentdistributioninbipolarelectrochemicalreactors,JournalofAppliedElectrochemistry38(2008)1259.[4] C. Comninellis, E. Plattner, P. Bolomey, Estimation of current bypass in a bipolar electrode stack from current-potentialcurves,JournalofAppliedElectrochemistry21(1991)415.


96

AbstractNo.102

Ion-solvatingpolymerelectrolytesforalkalinewaterelectrolysis

DavidAilia,MikkelRykærKraglund,aKatjaJankovaa,AndrewG.Wrightb,StevenHoldcroftbandJensOlufJensenaaDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,Kemitorvet207,DK-2800Kgs.

Lyngby,DenmarkbDepartmentofChemistry,SimonFraserUniversity,8888UniversityDrive,Burnaby,BritishColumbia,CanadaV5A

[email protected]

Summary.Polybenzimidazolemembranes imbibedwithaqueousKOHshowexcellentperformance inalkalinewaterelectrolysis.Thiscontributiondescribesthefundamentalphysicochemicalpropertiesofsuchmembranesandextendstoadiscussionaboutstabilityconcernsanddegradationmitigationstrategies.

Abstract. Poly(2,2’-(m-phenylene)-5,5’-bibenzimidazole) (m-PBI) belongs to a large family of polymers withbenzimidazole groups as a part of the polymer repeat unit. It is the most thoroughly studied polybenzimidazolederivativeandisrecognizedforitsexcellentthermo-mechanicalproperties,chemicalstabilityandgoodfilm-formingcharacteristics.Itishighlyhydrophilicandduetoitsamphotericnatureitstronglyinteractswithandabsorbsaqueousacidsandbases,suchaspotassiumhydroxide(Figure1).

Figure1Thechemicalstructureofm-PBIintheneutralpristineform(left)andinthepotassiumpoly(benzimidazolide)(right).

When equilibrated in 15-25 wt% aqueous KOH it forms a ternarym-PBI/KOH/H2O electrolyte system with a totalpolymerweightfractionoflessthanhalfthetotalweight.1TheabsorbedaqueousKOHsupportsremarkablyhighionconductivity,whichmakesitsuitableaselectrolyteandelectrodeseparatorinalkalinewaterelectrolyzers.2,3Byfurtherdevelopmentofelectrodesandcells,suchsystemsarenowapproachingperformancesthatarecomparablewiththatoftheprotonexchangemembraneelectrolyzers.4

This contribution describes the fundamental physicochemical properties of polybenzimidazole-based ion-solvatingpolymerelectrolytes,whichstronglydependontheconcentrationofthesurroundingsolution.Itextendstoadiscussionabout long-term stability concerns in aqueous KOH5 as well as under operational conditions3 and briefly presentsstrategiesformitigatingdegradation.6

1D.Aili,K.Jankova,J.Han,N.J.Bjerrum,J.O.JensenandQ.Li,Polymer2016,84,304-310.2D.Aili,M.K.Hansen,R.F.Renzaho,Q.Li,E.Christensen,J.O.Jensen,N.J.Bjerrum,J.Membr.Sci.2013,454,351-358.3M.R.Kraglund,D.Aili,K.Jankova,E.Christensen,Q.Li,J.O.Jensen,J.Electrochem.Soc.2016,163,F3125-F31314M.R.Kraglundetal.,Inmanuscript.5D.Aili,K.Jankova,Q.Li,N.J.Bjerrum,J.O.Jensen,J.Membr.Sci.2015,492,422-429.6D.Aili,A.G.Wright,M.R.Kraglund,K.Jankova,S.Holdcroft,J.O.Jensen,J.Mater.Chem.A2017,Inpress.


97

AbstractNo.103

Nickel/Tungsten-CarbideCompositeCatalystsforOxygenEvolutioninAlkalineWaterElectrolysis

DongHoonSonga,MinJoongKimaandEunAeChoa*aDep.OfMaterialsScienceandEngineering,KAIST,DaejeonGuseong-dong373-1,RepublicofKorea

[email protected]

Summary.

Nickel/Tungsten-carbide(Ni/WC)compositecatalystsforoxygenevolutionreactionweresynthesizedusingWCasaparentmaterial,andNiforanactivecatalystmaterial.TheOERactivityoftheNi/WC(η@10mA/cm2)showedonly324mV,andthisperformancewasmainlyattributedtoitspropertychangeoriginatedfromthebimetallicinterface.

Abstract.

Hydrogen,producedbyelectrolysis,isoneofthemostpromisingsystemstostoreelectricitycomingfromrenewablesandtosolveitsintermittency.Duetotheincreaseofglobalelectricitysharefromrenewableenergysources,large-scalestoragesystemsarerequired.Alkalineelectrolysiscanbeasuitablesolutionforthelarge-scaleenergystoragesystem.However, high overpotential and slow kinetics, particularly of the oxygen evolution reaction (OER), still limit theefficiency of the system. To enhance the efficiency of alkaline electrolysis cells, catalystswith high electrocatalyticactivityforOERshouldbedeveloped.

One suggestedmethod to increase the catalytic activityof a catalyst is tomakebimetallic interface, andmodifypropertiesofmaterials. Inthisstudy,nickel/tungsten-carbide(Ni/WC)compositewith largebimetallic interfacewassynthesizedtoincreasetheOERcatalyticactivity.Tungstencarbidewasusedasahostmaterial,andnickelwaschosenasametallayerforanactivematerial.Ni/WCshowedsuperiorcatalyticactivitythanNinanoparticleandWC(Figure1).The overpotential of Ni/WC for OER at 10mA/cm2 was only 324mV, and it was lower OER activity than that ofcommercialIr/Ccatalyst.Inaddition,Ni/WCshowedexcellentstabilityin1MKOHsolution(Figure2).

To investigate the origin of the outstanding performance of Ni/WC, various techniques such as TEM, XPS, andelectrochemical experiments were employed, and this performance was probably due to a change in the nickelcharacteristicsresultingfromthebimetallicinterface.

Figure1.OERactivityofWC,Ni,andNi/WCcatalystsinAr-saturated1MKOHsolution

Figure2.DurabilitytestforNi/WCinAr-saturated1MKOHsolution


98

AbstractNo.104

Bubblecharacterizationinanelectrolysiscellusingaflowvisualizationsystem

ErnestoAmoresaaCentroNacionaldelHidrógeno,ProlongaciónFernandoElSantos/n,13500Puertollano(CiudadReal),Spain

[email protected]

Summary.Thevelocityandsizeofindividualbubblesinsideanalkalinewaterelectrolysiscellhavebeenstudiedusingaflowvisualizationsystem.Thebubblesdiameterhasbeenmeasuredatdifferentcurrents,temperaturesandflowratestodeterminetheinfluenceofoperatingconditions.Theresultswereadjustedtodifferentstatisticaldistributions.

Abstract.Figure1ashowstheexperimentalalkalinewaterelectrolysisset-upusedinthisstudy.AscanbeappreciatedinFigure1c,theelectrolysiscells(ELECTROCELL,MicroFlowCell)havebeenmodifiedtoincludea10mmtransparentwindow(PMMAframe)betweenelectrodesanddiaphragm.APIV(Particle ImageVelocimetry)system,providedbyDANTECDynamics,consistingofaNd:YAGlaserandaCMOScamera(1000fps)allowstheflowvisualizationandthecharacterization of the gas bubbles generated during electrolysis inside the cell (Figure 1b). Direct visualization ofbubbleswithinatransparentcontainerhasbeenusedpreviouslybyothersauthors[1,2].

Figure1.Experimentalset-up:(a)cellelectrolysistestbench;(b)PIVsystem;(c)transparentcell;(d)gasbubblesinsideacell

Thehydrogenbubblediameterhasbeendeterminedbycapturing200 images in196ms(Figure1d)foreachofthecurrentdensitiesinvestigated(5-300mA/cm2).However,thereisadensitycurrentvalue(dependingonexperimentalconditions)abovewhich,thecellisfilledwithgasandtheflowvisualizationsystemcannotclearlydistinguishindividualbubbles.Thisprocedurehasbeenrepeatedatdifferentflowrates(naturalconvection-2.8l/min)andtemperatures(30-70°C)todeterminetheinfluenceofexperimentalconditionsonparticlesizedistribution.Also,thepolarizationcurveandtheFaradayefficiencyweremeasuredandcomparedinalltests[3].

Thebubblessizedatahavebeenadjustedtodifferentstatisticaldistributions(Figure2a).Later,theKolmogorov-Smirnovtestwasusedtodeterminethebeststatisticaldistributioninthisstudy.Accordingtotheexperimentaldata,themeanbubblediameterincreaseswithcurrent(Figure2b)anditdecreaseswithhigherflowrates(Figure2c).

Figure2.Bubblediameter:(a)experimentalandstatisticaldistribution;(b)atdifferentcurrentdensities;(c)atdifferentflowrates

[1]FlowMeasInstrum200516pp.35;[2]N.Nagaietal.WorldHydrogenEnergyConference.Lyon2006;[3]IntJHydrogenEnergy201439pp.13063


99

AbstractNo.105

AFacileSynthesisofNano-sizedIrO2andRuO2CatalystsfortheOxygenEvolutionReactioninAlkalineMedium

TamD.Nguyena,b,GüntherG.Schererc,ZhichuanJ.Xua,b,daSchoolofMaterialsScienceandEngineering,NanyangTechnologicalUniversity,Singapore

bEnergyResearchInstitute@NanyangTechnologicalUniversity,SingaporecTUM-CREATE,1CreateWay,138602,Singapore

dSolarFuelLaboratory,SchoolofMaterialScienceandEngineering,NanyangTechnologicalUniversity,SingaporeE-mail:[email protected]

Summary.Afacilewet-chemicalmethodforsynthesizingIrO2andRuO2nanoparticles(NPs)fortheoxygenevolutionreactioninalkalinemedium.

Abstract.

Theefficiencyof thewaterelectrolysisprocess ismainly restrictedby the sluggishkineticsof theoxygenevolutionreaction (OER).Many catalysts have been developed to improve the kinetics of theOER and therefore the overallefficiencyofthewaterelectrolysis.Amongofthem,IrO2andRuO2aretwoofthemosteffectivecatalystsforOER.Duetothehighcostandlowelementalabundance,IrO2andRuO2informofnanoparticlesareoftenusedtooptimizethemassefficiency.However,findinganeffectivesyntheticmethodtoproducesmallsizeIrO2andRuO2NPsstillremainschallenging.Inthisreport,afacilewet-chemicalmethodforsynthesizingIrO2andRuO2nanoparticles(NPs)fortheOERwasintroduced.Thenanoparticlesweresynthesizedbyreducingmetalchloridesinethyleneglycolinthepresenceofpolyvinylpyrrolidone,followedbyannealinginairatdifferenttemperaturestocontroltheparticlesize.TheactivityofIrO2andRuO2NPssupportedoncarbonblack(acetylenecarbon)wasinvestigatedbycyclicvoltammetry(CV)inalkaline(0.1MKOH)electrolyte.As-synthesizedIrO2andRuO2NPsindicatedhighcatalyticactivityfortheOER.TheIrO2NPsexhibitedaspecificactivityofupto3.5(±1.6)μA/cm2

oxideat1.53V(vs.RHE),whiletheRuO2NPsachievedavalueof124.2 (±8)μA/cm2

oxide.Formassactivity,RuO2NPsshowedavalueupto102.6 (±10.5)A/goxideat1.53V (vs.RHE),representingthehighestvaluereportedintheliteraturetodate.Moreover,acorrelationbetweenspecificactivityandcrystalorientationof IrO2andRuO2NPswasalsoobserved,whichcanbeconsideredasoneof themaingoverningfactorsfortheOERactivity.


100

AbstractNo.106

DFTstudiesofdopedCobaltandNickelOxyhydroxideCatalystsforOxygenEvolution

VladimirTripkovica,HeineA.Hansena,JuanMariaGarciaLastraa,TejsVeggeaaDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,2800Kgs.Lyngby,Denmark

[email protected]

Summary. Using density functional theory we study the complex interplay between catalyst structure, activity,electronicconductivityandstabilityfordopedandun-dopedcobaltandnickeloxyhydroxidecatalystsfortheoxygenevolutionreaction.

Abstract.We use Density Functional Theory to study Nickel and Cobalt oxyhydroxides as catalysts for the oxygenevolutionreaction(OER) inneutralandalkalinemedia.We investigatetheactivityofmodeloxideedgeandterraceterminationsonbulkand2Dnanosheetscatalysts.

WefindtheOERtakesplaceonoxygenlatticesitesthroughthe*OH,*O,*OOH,and*Ovacintermediates,andthatwhiletheactivityofcobaltoxyhydroxides increasessubstantiallyfrombulkstructurestonanosheets,theactivityofnickeloxyhydroxidesisratherinsensitivetothestructure.

Weinvestigatethechanges incatalystactivityandelectronicconductivity inducedby25differentdopantsstableatalkalineconditions.Fromouranalysis,weidentifyCrandFedopedcobaltoxyhydroxide,andV,Fe,Ru,IrandRhdopednickel oxyhydroxide, as the best catalysts, with Rh doped Ni ox-hys exhibiting the highest activity. The electronicconductanceofthedopedoxyhydroxideschangesasafunctionofthedopantatom’svalence,whichisafunctionoftheappliedpotential;e.g.Fe4+isaconductivespeciescomparedtonon-conductiveFe3+.

Figure:OERintermediatesonacobaltoxyhydroxidenanosheet.

ThisworkwassupportedbytheHorizon2020framework,grantnumber646186.


101

AbstractNo.107

A3-DmicroporousCo-Fe-Pcatalystforoxygenandhydrogenevolutionreactionsinalkalinewaterelectrolysis

HyoWonKim,SeKwonOh,EunAeChoandHyukSangKwon

DepartmentofMaterialsScienceandEngineering,KoreaAdvancedInstituteofScienceandTechnology

E-mail:[email protected]@kaist.ac.kr

Summary. A 3-D micro porous Co-Fe-P foam catalyst was fabricated by electrodeposition method on a Cu foamsubstrate.OverpotentialoftheCo-Fe-Pfoamcatalystat10mA/cm2was294mVforOERand73mVforHERinthe1MKOH,whichwassuperiortothenoblemetalcatalysts.

Abstract.Recently,hydrogenenergyhasbeenattractingattentionowingtodepletionoffossilfuelsandglobalwarming.Hydrogencanbeproducedbywaterelectrolysiswithoutconsumptionoffossilfuels.However,highoverpotential isrequiredfordecomposingwaterintheactualwaterelectrolysisreactionandefficiencyoftheelectrolysisisaround60%. Therefore, researches on electrochemical catalysts have been carried out to reduce the overpotential of theelectrolysisreactions.Transitionmetalphosphidecatalystshavebeenstudiedascatalystsforthehydrogenevolutionreaction(HER)andtheoxygenevolutionreaction(OER)inanalkalineenvironment.Inthepreviousstudies,mostofthecatalystsweresynthesizedviamulti-stepprocesses invokinghighcost, time-consumptionanduseof toxic chemicalproblems.Inthisstudy,a3-DmicroporousCo-Fe-PfoamcatalystwasfabricatedbyoptimizedCo-Fe-PelectrodepositiononaCufoamstructure.TheCo-Fe-Pfoamwiththicknessofabout15µmwaselectrodepositedwithoutcloggingthepore.OverpotentialoftheCo-Fe-Pfoamcatalystat10mA/cm2was294mVforOERand73mVforHERinthe1MKOH.Inaddition,towardHER,theCo-Fe-Pfoamcatalystexhibitedoverpotentialof70mVinthe0.5MH2SO4.TheseresultsdemonstratethattheCo-Fe-PfoamcatalysthadexcellentHERandOERactivity,superiortothenoblemetalcatalysts.TheimprovedperformanceofCo-Fe-Pfoamwasattributedtolowchargetransferresistanceandhighelectrochemicalactivesurfacearea(ECSA)causedbyhighlyporousfoamstructure.


102

AbstractNo.108

Processintensificationofalkalinewaterelectrolysisbyusing3-Delectrodes

QuentindeRadigues,ThomasDalneandJorisProost

InstituteofMechanics,MaterialsandCivilEngineering(iMMC),UniversitécatholiquedeLouvain,

B-1348,Louvain-la-Neuve,[email protected]

Summary.Inthispresentationwewillshowhow3Delectrodesandaforcedelectrolyteflowwillallowtoachievethenecessaryprocessintensification(P.I.)foralkalinewaterelectrolysis.Thesecondpartwillshowhowthistechnologycanbescaledupinapilotplantset-upofrepresentativeindustrialscale.

Abstract. Hydrogen is a promising and well-accepted energy vector to store electricity produced by intermittentsources, such as solar panels and wind turbines. In order to be cost effective, the water electrolysis needs to beintensified(higherproductioninsmallerunits)andscaleduptothematchthepowerofelectricitysources

Thecurrentworkfocusesonasimplewaytoincreasetheefficiencyofwaterelectrolysisbytheuseof3-Delectrodesand forcedelectrolyte flow.Suchmacro-porouselectrodesallowtoreducethecathodicoverpotentialcomparedtostateoftheart2-Dplateelectrodes.Undernaturalconvectiontheproducedgasbubblestendtoblockthe3-Dstructurereducingitsbenefit.Thankstotheforcedflow,thegasbubblesareforcedoutofthe3-Delectrodes.

AtypicalresultisshowninFigure1.AccordingtotheelectrokineticButler-Volmerequation,ahighercurrentdensityrequires a higher overpotential. Therefore, since for the same applied current the current density decreases withincreasingspecificelectrodearea,therequired(over-)potentialtodrivethemacroscopiccurrentwillbelowerforthe3-Delectrodecomparedtoa2-Delectrode.Forthisreasontheuseof3-DelectrodeswillreducethecellvoltageforagivenappliedcurrentasitcanbeseeninFigure1.

InFigure2,wecanseetheinfluenceofthecatholyteflowrateonthecellvoltage.Atlowerflowrate(v1)theproducedhydrogen bubbles tend to block the 3-D structure of the electrode, reducing the surface area in contactwith theelectrolyte.Increasingtheflowrate(v3tov9)willforcedebubblesoutoftheelectrodeallowingtotakefulladvantageoftheirhighsurfacearea.

Figures1and2wereobtainedinabenchtoplaboratoryexperiment.Futureworkwillfocusonimplementationoftheseresults in a pilot plant setup. The latter has a size representative for an industrial production equipment. Ourpresentationwillshowtheresultsofthisscale-up.

Figure9:Cellvoltagevstheappliedcurrentfora2-Delectrodeandvarious3-Delectrodesofdifferentporesize.

Figure10:Influenceofthecatholyteflowrateonthecellvoltagefora3-Delectrodeof800µmporesize.

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103

AbstractNo.109

DonQuichote:DemonstrationofHowtoProduceHydrogenUsingWindEnergy

G.Tagliabue*,A.EssamAly*,W.vanderLaak**-J.Vaes****FAST–FederazioneAssociazioniScientificheeTecniche,Milano

**WaterstofNet***Hydrogenics

[email protected],anEU-fundeddemonstrationproject,isprovingthecommercialviabilityofanintegratedhydrogenstoragesystemlinkedtoarefuellingfacility,directlyconnectingintermittentrenewableelectricitytotransportapplications.

Withacompletehydrogen-basedenergysystemestablishedatacommercialsitenearBrussels,theDonQuichoteteamisusingelectricityfromsolarpanelsandawindturbinetogeneratehydrogenthroughelectrolysisthatisthenusedforback-uppowersupplyandtorefuelfuelcell-poweredforklifttrucksandothervehicles.Thesystemprovedtobeasuccess–bothintermsofefficiencyandcosts.

IndexTerms–hydrogen,fuelcelltechnology,hydrogenstorage,renewableenergy

Abstract.Undertheco-ordinationofHydrogenicsEurope,theparticipantsintheprojectareHydrogenEfficiencyTechnologies,WaterstofNetvzw,EstablishmentFranzColruytNV,TUVRheinlandIndustrieServiceGmbH,JRC-JointResearchCentre-EuropeanCommission,PEInternationalAG,IcelandicNewEnergyLtdandFAST.

DonQuichoteisco-financedbytheFCHJU(July2012-June2017)andwanttodemonstratethetechnicalandeconomicfeasibilityofhydrogenstorageforelectricityfromrenewableenergy.

HydrogenstorageplaysanimportantrolebecauseitallowstheachievementofEuropeancarbonreduction.Thisprojectresultsinmuchmoreefficiency,butthecomplexityandthecostsofthesesolutionshavepreventedlarge-scaledemonstrations.

II.OBJECTIVESANDCONTENTS

Thisprojectbringsinnovationsanddemonstrationsas:

• Extensivetestingoftheexistingsystem,focusedondynamicbehavior,efficiencies,andavailability

• DoublingthehydrogencapacitybyaddingaveryefficientanddynamicPEM-electrolyser(storage130kg/day)

• Developing,testing,demonstrationandvalidationofdirectcouplingbetweenwindturbine(1,5MW)andsolarpanels(1050kW)andtheelectrolysertechnology

Thedemonstrationsprogramsconsistofthreephases,everyoneislongtwelvemonths(8000hoursperphase),intotal24000hours.

• Phase1:Adaptationofexistinghydrogenfuelsystem(electrolyser,compressor,storage,fuelingforklifts)

• Phase2:Research,additionalstorageandafuelcellsystem,thelatestforactivebalancingthegrid

• Phase3:Research,developmentandbuildofanewsystemforefficient,compact,modularcompressionandexpansionofhydrogen.


104

AbstractNo.110

DesigningMegawattsizePEMwaterelectrolysers

AlejandroOyarcea,AbdelghafourZaabouta,PaulSkjetnera,TrondBergstøma,andMagnusThomassenaaSINTEFMaterialsandChemistry,Trondheim,Norway

[email protected]. The EU-funded projectMEGASTACK (FCHJU) aims at reducing the cost ofmegawatt size PEMelectrolysersbydesigningandproducinglargeareamegawattsizedPEMwaterelectrolysers.However, inordertoachievemaximumperformanceandlonglifetime,itisimportanttohaveaclearunderstandingoftheprocessesoccurringwithineachcellinastackandtotranslatethisunderstandingintotoolsthatcanaidin cell and stack design. As part of the MEGASTACK project, significant effort has been made in thedevelopment ofmathematicalmodels for different scales. This paper presents the current status of theeffortswithintheMEGASTACKproject,andinparticular,theeffortsmadeindevelopingatwophaseflowmodelsforinvestigationoftheliquidandgastransportintheanodeflowfieldofalargescalePEMelectrolysiscell.

Abstract.

Thetwo-phaseflowmodelisbasedonthevolumeoffluid(VOF)modelinANSYS/Fluent16.2andimplementsasub-gridscalemodelsforwaterelectrolysisasasetofuser-definedfunctions.Thesesub-gridscalemodelsinclude,gasnucleation,gas-liquidmasstransferandbubblecoalescenceandbreakupphenomenaonsub-gridlengthscales.Experimentsusingatransparentcellincombinationwithahigh-speeddigitalcameraaswell as numerical image processingwas used to quantify temporal and spatial gas distribution and flowvelocities.

Theexperimentalresultsarecomparedtothetwo-phaseflowmodelresultsandthevalidityandimplicationsofthemodelarediscussed.Itisclearfromboththemodellingworkandexperimentalresults,thatinletand

outlet manifolds, as well as theflow resulting from specificchoices for current collectorgreatly impacts the waterdistribution of the electrolyserstack and therefore also on thegasdistributionwithinthecell.

Fig 1. Two-phase flow simulationshowingtheOxygenvolumefractionof a large area (1000 cm2) waterelectrolyserat1.5Acm-2.


105

AbstractNo.111

FromPolyelectrolytestoRobust,HighlyProtonConductingHydrocarbonMembranesforPEMFuelCellandPEMElectrolysisApplications

TorbenSaatkampa,AndreasMünchingera,GiorgiTitvinidzebandKlaus-DieterKreueraaMaxPlanckInstituteforSolidStateResearch,Heisenbergstraße1,D-70569Stuttgart,Germany

bAgriculturalUniversityofGeorgia,0131Tbilisi,240DavidAghmashenebeliAlley,[email protected]

Abstract.Here,wepresenta familyofmembranesmakinguseof theamazingpropertiesofhighly sulfonatedpoly(phenylenesulfone)sastheirkeyconstituent.Itistheparticularelectronicstructureofthispolyelectrolyteanditshighdensityofionicgroupswhichleadstoacombinationofhighchemicalstability[1,2],superiorprotonconductivity[3-5]andlowelectroosmoticwaterdrag[3].Sincepuresulfonatedpoly(phenylenesulfone)sshowsalt-likebehaviour,i.e.brittleness in the dry state and exaggerated swelling or even dissolution in water [2-5], we have used thesepolyelectrolytesasconstituentsofpolymerblendsforformingrobustmembranes.[6,7]Thesemembranescombinetheadvantageouspropertiesofpurepoly(phenylenesulfone)swithmechanicalrobustnessneededfortheirapplicationinPEMfuelcellsandPEMelectrolyzers.AscomparedtoPFSAmembranes(e.g.Nafion),theymaybeconsideredtobehigh-T membranes with higher activation enthalpy for all transport coefficients, low gas-crossover even at hightemperatureandmechanicalpropertieswhicharealmostindependentoftemperature(T<180°C).

References:

[1] M. Schuster, K. D. Kreuer, H. T. Andersen, J. Maier, Macromolecules 2007, 40 (3), 598.[2] V.Atanasov, M. Buerger, A. Wohlfarth, M. Schuster, K.D. Kreuer, J. Maier, Polymer Bulletin 2012, 68, 317.[3]C.C.deAraujo,K.D.Kreuer,M.Schuster,G.Portale,H.Mendil-Jakani,G.Gebel,J.Maier,Phys.Chem.Chem.Phys.2009,11(17),3305.[4]G.Titvinidze,K.D.Kreuer,M.Schuster,C.C.deAraujo,J.Melchior,W.H.Meyer,Adv.Funct.Mater.2012,22,4456[5]M.Schuster,C.C.deAraujo,V.Atanasov,H.T.Andersen,K.D.Kreuer,J.Maier,Macromolecules2009,42(8),3129.[6]K.D.Kreuer,S.Takamuku,G.Titvinidze,A.Wohlfarth,W.H.Meyer, PatentEP2902431-A1;WO2015117740-A1.[7]M.Schuster,K.D.Kreuer,A.H.Thalbitzer,J.Maier,PatentDE102005010411-A1;WO2006094767-A1;EP1856188-A1; KR2007122456-A; CN101171284-A; JP2008533225-W; US2008207781-A1; RU2423393-C2; CN101171284-B;US8349993-B2;US2013079469-A1;KR1265971-B1;CA2600213-C;JP5454853-B2;US8846854-B2.


106

AbstractNo.112

InvestigationonporoustransportlayersforPEMelectrolysis

ArneFallischa,JagdishkumarGhinaiyaa,KoljaBrombergera,MaximillianKiermaiera,ThomasLickertaandTomSmolinkaa(pleaseunderlinepresenter)

aFraunhoferInstituteforSolarEnergySystemsISEHeidenhofstrasse2,D-79110Freiburg

[email protected]

Summary:Thisworkinvestigatesporoustransportlayersusingin-andex-situmeasurementstechniquestounderstandmasstransportlimitation.Theinfluenceofpermeability isstudiedincelldesignswithandwithoutflowfield.Anewquantity,namelythegastransportabilityisestablished,whichcorrespondstomasstransportlimitation.

Abstract:

Poroustransportlayer(PTL)playsanessentialroleinPEMelectrolysiscellstotransportgasandwaterandelectricalcurrent.ThemasstransportlimitationisobservedathighcurrentdensitiesinPEMelectrolysiscell[1],whichhasgivencomparatively less concern in literature to date. To analyse the phenomena ofmass transport limitation,we havestartedtobuildupafundamentalunderstandingbycomprehensiveex-situandin-situcharacterisation.Tostudyporesize distribution and porosity mercury intrusion porosimetry is used. Capillary flow porometry (CFP) is used toinvestigatethrough-planegaspermeabilityandporesizeandpermeatryisusedtodeterminein-planeabsolutewaterandgaspermeability.Besides thesestandardmethodsweusedtheCFPtodevelopedanewmethodto investigatecapillary pressure versus liquid saturation relation and to get access to contact angle inside PTL structures. In-situmeasurementswerecarriedoutinaspecialdesigned25cm²electrolysistestcell.Error!Referencesourcenotfound.showsthemethodologyusedfortheinvestigation.ResultsofpolarisationcurvesinFigure12arecomparedagainstresultsofex-situcharacterisation.Itisfoundthatforcelldesignswithoutflowfieldthein-planepermeabilityplaysacrucialroleregardingmasstransportlimitation.Anewquantityisestablished,whichisnamegastransportability,whichexplainstheabilityofPTLtotransportgasfromcatalystlayertotheflowchannelatagivencurrentdensity.AnincreaseingastransportabilityofwettedPTLreducesvoltage lossduetomasstransport limitation inthepolarizationcurve.Usingtheproposedtechnique,theapplicabilityofanyPTLcanbequantifiedforPEMelectrolysiscellswithflowfield.

Figure11:Approachedmethodology Figure 12: Polarization curves without flow field fordifferentporoustransportlayers.

References

[1] C.H.Lee,R.Banerjee,F.Arbabi,J.Hinebaugh,andA.Bazylak,“PorousTransportLayerRelatedMassTransportLossesinPolymerElectrolyteMembraneElectrolysis:AReview,”inASME201614thInternationalConferenceonNanochannels,Microchannels,andMinichannelscollocatedwiththeASME2016HeatTransferSummerConferenceandtheASME2016FluidsEngineeringDivisionSummerMeeting,V001T07A003.

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107

AbstractNo.113

Acceleratedstresstestsforefficientdegradationstudiesoniridium-basedmixedmetaloxidecatalystsforPEM-electrolysis

CamilloSpöria,CorneliusBranda,DavidP.WilkinsonbandPeterStrasseraaTUBerlin,TheElectrochemicalCatalysis,EnergyandMaterialsLab,Straßedes17.Juni124,10623Berlin,Germany

bUBC,DepartmentofChemicalandBiologicalEngineering,2360EastMall,VancouverBCV6T1Z3,[email protected]

Summary.

Recentlyproposedacceleratedstresstests(ASTs)areappliedtogainnewinsightintofactorsgoverningcatalyststabilityduringelectrochemicalwateroxidation.

Abstract.

Duetotheintermittentnatureofrenewableenergies,currentendeavorsinsustainableenergyarestronglydependenton reliable energy storage solutions.1 Storing energy in the chemical bonds ofmolecular hydrogen produced from(photo)-electrochemicalwatersplittinghasproventobeoneofthepromisingstrategiestocounteractthisdrawback.2Whileseveralwatersplittingtechnologies(liquidorsolidelectrolyte,pressurized,lowandhightemperature,etc.)haveemerged,andwholecatalystfamilieshavebeeninvestigated,withrespecttoactivity,muchremainsunknownaboutthemechanismofwatersplitting,especially theoxygenevolutionreaction (OER)at theanodeside.3Evenmoreso,potentialfactorsdeterminingstabilityofsuitableOERcatalystshavebeenmostlydisregardedandincontrasttofuelcellresearchstandardizedprotocolsandcommonfiguresofmeritaremissing.ThereareseveralotherstabilityissuestoaddressinPEM-Electrolysisbuttogetherwiththeneedforcost-reductionandlowercatalyst-loadings,findingreliableiridium-basedmixedmetaloxidecatalystshasbecomecrucial.4

Recently,wehaveproposedaseriesofacceleratedstresstest(AST)protocolsandfiguresofmeritforOERcatalyststoadvancecomparability–andprogress–inOERresearch.5InthisstudywereporttheapplicationoftheseASTprotocolstotestperformanceanddurabilityofiridium-basedmixedmetaloxidecatalystsfortheOERinPEMwaterelectrolysisdevices. Thorough physicochemical characterization combinedwith nondestructive pre-/post-catalysis screening ofcatalystcompositionandonlineanalysisofcatalystdecompositionareusedtoidentifyandmonitorstability-governingfactors.

IdentifyingthedegradationmechanismsduringOERmayopenthewaytowardsnewcatalystdesignsthatcouldbreaktheinverserelationbetweencatalystactivityandstability.NewcatalystswithcomparableactivitytopureiridiumoxidecatalystsbutwithincreasedstabilityandreducedcostwouldimprovefurthercommercializationofPEM-Electrolysis.

1. Smolinka,T.;Günther,M.;Garche,J.NOW-Studie:StandundEntwicklungspotenzialderWasserelektrolysezurHerstellungvonWasserstoffausregenerativenEnergien;FraunhoferISE,FCBAT,NOWGmbH:07/05/2011,2011;p53.2. Carmo,M.;Fritz,D.L.;Merge,J.;Stolten,D.,AcomprehensivereviewonPEMwaterelectrolysis.IntJHydrogenEnerg2013,38(12),4901-4934.3. Reier,T.;Nong,H.N.;Teschner,D.;Schlögl,R.;Strasser,P.,ElectrocatalyticOxygenEvolutionReactioninAcidicEnvironments-ReactionMechanismsandCatalysts.AdvancedEnergyMaterials2016,1601275.4. Chang,S.H.;Connell,J.G.;Danilovic,N.;Subbaraman,R.;Chang,K.C.;Stamenkovic,V.R.;Markovic,N.M.,Activity-stabilityrelationshipinthesurfaceelectrochemistryoftheoxygenevolutionreaction.FaradayDiscuss2014,176,125-133.5. Spoeri,C.;Kwan,J.T.H.;Bonakdarpour,A.;Wilkinson,D.P.;Strasser,P.,TheStabilityChallengesofOxygenEvolving Electrocatalysts: Towards a Common Fundamental Understanding andMitigation of Catalyst Degradation.AngewandteChemieInternationalEdition2016.


108

AbstractNo.114

Directmembranedeposition–asimpleandcosteffectivefabricationmethodforpolymerelectrolytemembraneelectrolysiscells

CarolinKlosea,MelanieBühlerb,NilsBaumanncandSimonThielea,b,d

aLaboratoryforMEMSApplications,IMTEKDepartmentofMicrosystemsEngineering,UniversityofFreiburg,79110Freiburg,Germany

bHahn-Schickard,78052Villingen-Schwenningen,GermanycFraunhofer-InstitutfürChemischeTechnologieICT,76327Pfinztal,Germany

dFIT,UniversityofFreiburg,79110Freiburg,[email protected]

Summary.Directmembranedepositionispresentedasanovelmanufacturingapproach.Itisaninversionofthestate-of-the-art fabricationmethodandallowsanoptimizedcatalystutilizationandasimplified fabricationprocedure forpolymerelectrolytemembranefuelcells(PEMFCs)(Figure1a).

Abstract.ForPEMFCstheadvantagesofdirectmembranedepositionhavealreadybeenshowninseveralpublications[1,2].Asstated,thedirectdepositionofthemembranein liquidformontotheelectrodesprovidesabettercontactbetweencatalystlayerandpolymerelectrolytemembrane(Figure1b)[3].Additionaltoalowercontactresistance,thismethodyieldsalowermasstransportresistance.

Wepresentthetransferofthisconcepttopolymerelectrolytemembranewaterelectrolysiscells.Thechallengeherebyistofabricatesmoothandhomogeneouselectrodesontitaniumbasedporoustransportlayersfortheanodesideinordertogetamembranelayerwithoutcrossoverandinternalelectricalshorting(Figure1c).Themembraneionomerisdeposited in liquid form onto these electrodes for example by inkjet-printing. This method also enables a simplefabricationofcompositemembraneswithnanoparticlesorelectrospunnanofiberstoincreasemechanicalandchemicalstability[4,5].

References[1] M.Breitwieser,M.Klingele,B.Britton,S.Holdcroft,R.Zengerle,S.Thiele,Electrochem.Commun.60(2015)168–171.[2] M.Klingele,M.Breitwieser,R.Zengerle,S.Thiele,J.Mater.Chem.A3(2015)11239–11245.[3] S.Vierrath,M.Breitwieser,M.Klingele,B.Britton,S.Holdcroft,R.Zengerle,S.Thiele,J.PowerSources326(2016)170–175.[4] M.Breitwieser,C.Klose,A.Hartmann,A.Büchler,M.Klingele,S.Vierrath,R.Zengerle,S.Thiele,Adv.EnergyMater.(2016)1602100.[5] M.Breitwieser,C.Klose,M.Klingele,A.Hartmann,J.Erben,H.Cho,J.Kerres,R.Zengerle,S.Thiele,J.PowerSources(2016).

a)b)c)

20µm

Figure13a)Aschematicofafuelcellfabricatedwithdirectmembranedeposition.b)DMDprovidesabettercontactbetweencatalystlayer(CL)andpolymerelectrolytemembrane(PEM).c)TitaniumfibersubstratecoatedwithIrO2toformacatalystlayer.


109

AbstractNo.115

Experimentalanalysisoflocaleffectsina50cmPEMwaterelectrolysiscell

ChristophImmerza,MartinSchweinsa,BorisBensmanna,*,MartinPaidarb,TomášBystroňb,KarelBouzekbandRichardHanke-Rauschenbacha

aLeibnizUniversitätHannoverbUniversityofChemistryandTechnology,Prague

[email protected]

Summary.Thiscontributionprovidesresultsofanexperimentalanalysisofthecurrentandtemperaturedistributioninasingle-channelPEMwaterelectrolysiswithalengthof50cm.

Abstract.PEMelectrolysisisapromisingtechnologytoprovideacouplingbetweenthethreemainenergysectorsheat,electricpowerandmobilityintheprospectivedecarbonizedenergysystem.State-of-the-artPEMwaterelectrolysiscellsaremainlyknownonalaboratoryscale.FabricatedPEMwaterelectrolysiscellsinMW-scalearesofarmainlyinstalledfordemonstrationpurposeswithhighpotentials inthekinetic, thermodynamicandflowdynamicoptimization.ThepresentcontributiongainsbetterunderstandingofthedetailedbehaviorofscaledupPEMwaterelectrolysiscells.

Forthispurposeasingle-channelPEMwaterelectrolysiscellof50cmlengthisobserved.Thecellisdividedinto250measurementsegments,allowingtodetectthedistributionofcurrentdensityandtemperaturealongthechannel.Suchlocal measurements provide additional information about the cell performance that are far beyond the integralinformation obtained from normal integral measurements. Identification of local temperature hot spots orinhomogeneouscurrentdensitydistributions,leadingtofasterdegradationandlossesincellperformance,getvisible.

Thisworkfocusesontheexperimentalinfluencesoftheoperationparametersmeancurrentdensity𝚤,cellvoltage𝑈$%&&theanodeandcathodetemperatures𝑇(\*andthefeedwaterflux𝑚,-.,01

( ontheintegralcellperformanceingeneralandonthedistributionofcurrentdensityandtemperaturealongthechannelinparticular.

Firstresultsshowthattheseinvestigationscangiveimportantadditionalinformationaboutthecellperformance:

• Feedwaterfluxvariationinfluencesthehomogeneityoflocalcurrentdensitydistributionalongthechannel.• Inhomogeneityofcurrentdensityandtemperatureshowsnoclearcorrelationwithintegralcellovervoltage,

e.g.despitelowintegralvoltagehighinhomogeneityofcurrentdensityandtemperatureispossible.• CharacteristiccurrentdensityprofilesofaCCMchangewithtimeenablingtheidentificationofactivationor

degradationprocesses.• Verylowfeedwaterfluxeschangewaterconsumptionrateslocallyanddynamically.• Currentdensityprofilesarehighlyinfluencedbyelectricalcontacting,e.g.differencesofCCMorCCEdesign.

Figure1:ScheduleofexperimentalPEMECforsegmentedcurrentdensityandtemperaturemeasurement

Acknowledgements:FinancialsupportbytheGermanResearchFoundation(DeutscheForschungsgemeinschaft,DFG)within the framework of the project grant HA 6841/2-1 and the Grant Agency of the Czech Republic within theframeworkoftheProjectNo.15-02407Jisgratefullyacknowledged.


110

AbstractNo.116

ModellingandSimulationActivitiesonPEMWaterElectrolysis

DeepjyotiBoraha,MarceloCarmoa,MartinMüllera,WernerLehnerta,baForschungszentrumJuelichGmbH,InstituteofEnergyandClimateResearch,IEK3:ElectrochemicalProcess

Engineering,52425Jülich,GermanybModellinginElectrochemicalProcessEngineering,RWTHAachenUniversity,Aachen,Germany

[email protected]

Summary.AdetailedreviewofPEMelectrolysismodellingandsimulationispresented.Startingfromearlyapproachesbaseduponpolarizationcurve tomicroandnanoscalemodellingofporous transport layer,achronological study iscarriedout.Differentactivitieshavebeencomparedandresearchgapsareidentified.

Abstract.PEMelectrolysisasamethodofproducinghydrogenbyusingelectricalenergyfromrenewablesourceshasreceivedmuchattentionrecently.ResearchinPEMwaterelectrolysisdomainisstillinitsearlystagesascomparedtoresearch in fuel cells. As with any other engineering research, this also involves theoretical approaches andexperimentation.Modelling and simulationof PEMelectrolyzer systems startednearly twodecades ago and it hasgottensignificanttractioninthepastfewyears.Thisinvolvessimpleanalyticalequationsto3Dflowsimulation,steadystatemodelstodynamicmodels,componentlevelmodelstosystemlevelmodelsormodelsintegratingphoto-voltaicsystems.Itisthereforeessentialtopresenttheresearchcommunityagoodoverviewoftheactivitiesthathavetakenplaceovertime.AcomprehensivereviewofPEMelectrolysissystemsingeneralhasbeenreportedbyCarmoetal.[1].BensmannandHanke-Rauschenbach[2]havealsoreportedabriefstudyonthemodelingofPEMwaterelectrolysissystems.Hereweaimtoprovidefurtherdetailsintothissubject.Wehavecomparedactivitiescarriedoutbydifferentgroupsandprovidedvaluableinsighttothecurrentstateoftheart.ItisfoundinstancethatOndaetal.[3]reportedoneof theearliestmodellingapproaches.NieandChen [4]have reporteda threedimensional computational fluiddynamics simulationof flow in the flow fieldplates.However,no suchactivitieshavebeen reportedafter2010. Inaddition, Oliveira et al. [5] have utilisedmicro and nanoscalemodels for porous electrodes and the catalyst layermodelling.Wehavealsocriticallyobservedthatmodellingofporouselectrodesandcatalystlayerstillrequiresfurtherdevelopment.

References:

[1] CarmoM,FritzDL,MergelJ,StoltenD.AcomprehensivereviewonPEMwaterelectrolysis.IntJHydrogenEnergy2013;38:4901–34.doi:10.1016/j.ijhydene.2013.01.151.

[2] BensmannB,Hanke-RauschenbachR.EngineeringModelingofPEMWaterElectrolysis:Asurvey.ECSTrans2016;75:1065–72.doi:10.1149/07514.1065ecst.

[3] OndaK,MurakamiT,HikosakaT,KobayashiM,NotuR,ItoK.PerformanceAnalysisofPolymer-ElectrolyteWaterElectrolysisCellataSmall-UnitTestCellandPerformancePredictionofLargeStackedCell.JElectrochemSoc2002;149:A1069.doi:10.1149/1.1492287.

[4] NieJ,ChenY.Numericalmodelingofthree-dimensionaltwo-phasegas-liquidflowintheflowfieldplateofaPEMelectrolysiscell.IntJHydrogenEnergy2010;35:3183–97.doi:10.1016/j.ijhydene.2010.01.050.

[5] OliveiraLFL,JallutC,FrancoAA.Amultiscalephysicalmodelofapolymerelectrolytemembranewaterelectrolyzer.ElectrochimActa2013;110:363–74.doi:10.1016/j.electacta.2013.07.214.


111

AbstractNo.117

Investigationofadvancedcomponentsinahighpressuresingle-cellelectrolyserforthedevelopmentofaHP-PEM-ELYstackaspartofaRegenerativeFuelCell

System

DimitriosΚ.Niakolasa,StylianosNeophytidesa,ConstantinosG.Vayenasb,AlexandrosKatsaounisb,NikolaosAthanasopoulosa,StellaBalomenouc,Kalliopi-MariaPapazisic,DimitriosTsiplakidesc,MaxSchautzd

aFoundationforResearchandTechnology,InstituteofChemicalEngineeringSciences(FORTH/ICE-HT),GR-26504Patras,Greece

bDepartmentofChemicalEngineering,UniversityofPatras,GR-56504,GreececCentreforResearchandTechnology-Hellas(CERTH),Greece

dEuropeanSpaceResearchandTechnologyCentre(ESTEC),[email protected]@iceht.forth.gr

Summary.TheobjectiveofthepresentedworkistheperformanceandtoleranceevaluationofselectedcomponentsandmaterialsforthedevelopmentofaHighPressure,PolymerElectrolyteMembrane(PEM)Electrolyser(HP-PEM-ELY)Stack,aimingtooperateat80barwithaperformanceoutputof0.3A/cm2at1.6V.

Abstract.Regenerative fuelcellsoffersignificantadvantagesover rechargeablebatteriesasenergystoragedevices,especiallyinapplicationswherehighspecificenergydensityisrequiredasinthecaseoftelecommunicationsatellites.AclosedloopregenerativePEMfuelcellsystem(RPEMFCS)operatesasahighpressurePEMelectrolyserwhenexcesspowerisavailablefromthesolararray(chargingmode/reactantregeneration)andasaPEMfuelcellwhenthesolararray does not generate power i.e. when the satellite is in eclipse (dischargemode). It has to bementioned thatoperationofanelectrolyserathighpressureisadvantageousdueto(i)reductionofinternalcellresistance,(ii)reductionofvolumeofgasbubbles,whichfacilitatesthetransportationofliquidwaterand(iii)productionofcompressedH2andO2,whichmakes theelectrolyser toperformat the same timeasagas compressor. In thisway, the installmentofexternal compressors can be avoided, which finally improves and simplifies the whole system`s integration.Regenerativefuelcells,ofadiscreteoraunitizeddesign,havebeenconsideredaspotentialenergystoragesolutionforfuturespacemissions [1],aswellas for terrestrialapplications.Theultimateobjectiveof thecurrentactivity is theresearchanddevelopmentofaregenerativePEMfuelcell(RPEMFC)systemforspaceapplications,targetingat(a)largetelecommunicationplatformsingeostationaryorbit,GEO(Commercialapplication),(b)planetaryexplorationmissions(Scienceapplication)andlastbutnotleast(c)terrestrial(CommercialandScience)applications.Basedonthematerialsresearchanddevelopment,whichhasbeencarriedoutuptonow,twostacks(ahigh-pressurePEMelectrolyserandahigh-temperature PEM fuel cell) are undermanufacturing and preliminary testing, aiming to be incorporated in aregenerativefuelcelltestbenchforfurtherevaluation[2].CompletetestingofthewholesystemwillbeperformedunderapredefinedloadprofileinaccordancetotheneedsofatelecomplatforminGEOorbit.Inthepresentedwork,anextensivestudywasperformedonasingle-cellhighpressurePEMelectrolysermanifold,leadingtoalistofmaterialswithsuitablepropertiesandengineeringsolutionstowardsspecificoperationrequirements.ThisinvestigationprovidedthenecessaryfeedbackforthedesignandmanufactureofaprototypeHP-PEM-ELYstack,whichisalsodiscussed.

AcknowledgmentsTheresearchleadingtotheseresultshasreceivedfundingfromtheEuropeanSpaceAgency(ESA)undertheprojectsGTF2065: “Regenerative PEM Fuel Cells” (Contract No. 22329/09/NL/CBI) and “Development of a Closed LoopRegenerativeHT-PEMFuelCellSystem”(ContractNo.4000109578/13/NL/SC).References[1]ESAElectrochemicalEnergyStorageRoadmap,2011.[2]ExecutiveSummaryReportfromactivityGTF2065:“RegenerativePEMFuelCells”(ESAContract22329/09/NL/CBI)


112

AbstractNo.118

PermeationandRecombinationofHydrogenunderPEMelectrolysisconditions

DmitriBessarabova,AndriesKrugeraandKrzysztofLewinskibaHySAInfrastructureCenter,North-WestUniversity,PrivateBagX6001,Potchefstroom,SouthAfrica

b3MCompanyCenter,Bldg.201-01-E-21,St.Paul,MN,[email protected]

Summary.RecombinationofhydrogenreducesitsconcentrationintheanodecompartmentofPEMelectrolysers.TheoriginofthehydrogenintheanodesectionofPEMelectrolyserisduetothepermeationtakingplacefromthecathodecompartment.Thistalkwillprovidesomedataandtheoreticalanalysisontheuseofplatinum(Pt)withintheanodeelectrodestructuretoreducehydrogenconcentrationduringPEMwaterelectrolysis.

Abstract.3MNSTFCCMswereusedaspermeationbarrierinPEMelectrolyser.TheywerecoatedwithIrandPtNSTFelectro-catalystontheanodeandcathodesidesrespectively.All-titaniummadecellwith25cm2activemembraneareawasusedinalltheexperiments.InonesetofexperimentsTi-basedplatinisedGDLwasusedandintheothersetofexperimentsgold-coatedtitanium-basedGDLwasusedontheanode.ThepermeationrateofhydrogenfromcathodetoanodecompartmentwasmeasuredbygaschromatographymethodtoanalysetheeffectofPtpresencewithintheGDLstructureontheconcentrationofhydrogenintheoxygenstream.Temperaturesaswellaswatersupplyrateandcurrentdensitieswerealsousedasvariables.


113

AbstractNo.119

DesignofReferenceElectrodeforPolymerElectrolyteMembraneElectrolyzer

E.Johnston-Haynes,S.R.Dhanushkodi,andB.A.Peppley

SustainableEnergyEngineeringQueen’sUniversityLaboratory(SEEQUL),DepartmentofChemicalEngineering,Queen’sUniversity,Kingston,Ontario

CorrespondingAuthorE-mailAddress[[email protected]]

Integrating hydrogen-based energy technologies are an effective strategy to decarbonize the electricity market.Hydrogen can be produced by electrolyzingwater and stored as an energy carrier. Polymer ElectrolyteMembraneElectrolysers(PEMEs)areapower-to-gastechnology,which iswellsuitedtoconverting intermittentelectricityfromrenewablesourcesintopurehydrogenandoxygen,duetotheirfastresponseandabilitytoacceptlargeinputpowersurges[1].AddingPEMEsintotheelectricitygridasanenergystoragetechnologywillhelptoimprovethereliabilityandstability[2-3].ThemajorityoftheelectroderesearchforPEMelectrolysishasfocussedontheoxygenevolutionreactionat theanode.Thecontribution topolarization losses fromthehydrogen-producingcathodehas receivedmuch lessattention.Thismaybe,inpart,duetoissueswithimplementingastableandreliablereferenceelectrode(RE).Severalconfigurations of internal and external type REs were investigated to separate the contribution of the anode andcathode tooverall cellpolarization.REefficacywasassessedbycomparing theagreementbetween theoverall cellpotentialandthesumoftheelectrodepotentials.UsingastableRE,wehavebeenabletoshowthattheoverpotentialofthecathode issignificantlyaffectedbythecrossoverofoxygenthroughtheNafionmembrane.Furthermore,thekineticandohmicparametersofthemembraneelectrodeassembly(MEA)werecalculatedfromthepolarizationcurves.Thecontributionofcathodepolarizationtocellperformanceisclearlyshowntobesensitivetothepartialpressureofoxygenattheanode,Figure1.Inaddition,thecathodicpolarizationdecreaseswithtemperatureinawaythatcanberelatedtothesolubilityofoxygeninwater.TheimplicationsofcontrollingoxygencrossoverpolarizationtooverallPEMEperformanceandlifetimewillbediscussed.

Figure.1.Referenceelectrodepolarizationcurvesforanode,cathode,andcellatoperatingpressures:-85kPaand

101kPa.References[1]Stiller,Christoph,JanMichalski,DetlefStolten,andThomasGrube."UtilisationofExcessWindPowerforHydrogenProductioninNorthernGermany."ReportNr.:SchriftendesForschungszentrumsJülich/Energy&Environment(2010).[2]Gahleitner,Gerda."Hydrogenfromrenewableelectricity:Aninternationalreviewofpower-to-gaspilotplantsforstationaryapplications."internationalJournalofhydrogenenergy38,no.5(2013):2039-2061.[3]Jentsch,Mareike,TobiasTrost,andMichaelSterner."Optimaluseofpower-to-gasenergystoragesystemsinan85%renewableenergyscenario."EnergyProcedia46(2014):254-261.


114

AbstractNo.120

Electrospun-TiO2SupportingmaterialsforOxygenEvolutionReactioninAcidicconditions

Eom-JiKima,MinJoongKima,EunAeChoa*aDepartmentofMaterialsScienceandEngineering,KoreaAdvancedInstituteofScienceandTechnology(KAIST),

RepublicofKoreaE-mail:[email protected]

Summary.Metaldoped-TiO2supportingmaterials(M-dopedTiO2)werepreparedbyusingelectrospinningmethodforoxygen evolution reaction in acidic conditions. Ir/M-doped TiO2 was synthesized and evaluated by linear sweepvoltammetry.PreparedIr/M-dopedTiO2catalystshowedbetterOERactivitythanIrblack.

Abstract. Polymer electrolyte membrane electrolytic cells (PEMECs) is one of appropriate energy storage systemsconnectedwithrenewableenergyduetohighdrivecurrentandenduranceunderroadfluctuation.Inwaterelectrolysis,oxygenevolutionreaction(OER)occursunderacidicandhighpotential.So,thelargeamountofpreciousmetalcatalystisneeded forperformanceand stability. Introductionof supportingmaterials could reduce theamountofpreciousmetal catalyst without performance degradation. Titanium oxide (TiO2) is one of fewmaterials which shows goodstabilityunderacidicandhighpotentialconditions.AlsolowelectronicconductivityofTiO2(~10

-6S/cm)canovercomewithintroductionofappropriatedopingelementintoTiO2.

In thiswork, variousmetal elementswere doped into TiO2 supportingmaterials.M-doped TiO2were prepared byelectrospinningmethod.Figure1(a)isaSEMimageofpreparednanofiberTiO2.M-dopedTiO2werecharacterizedtostudy physical and chemical properties. Then, iridium catalysts onM-doped TiO2 support (Ir/M-doped TiO2) weresynthesizedbypolyolmethodandwereelectrochemicallyevaluated.OERactivityofpreparedcatalystswasmeasuredbylinearsweepvoltammetryinoxygen-saturated0.5MH2SO4,respectively.Asshowninfig.1(b),polarizationcurvesforeachcatalystswerechangedasvariationofdopingelements.Ir/M-dopedTiO2showshigherOERactivitythaniridiumblack.Fromtheseresults,itwasobtainedthatintroductionofdopantintoTiO2changethecharacteristicsofTiO2andthischangecontributetoimprovementOERactivity.Ir/M-dopedTiO2couldbesuggestedOERcatalysttoreducetheamountofpreciousmetalcatalystwithoutperformancedegradation.

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7

0

5

10

15

20 Ir black Ir/W-doped TiO2

Ir/Nb-doped TiO2

Cur

rent

den

sity

(mA

cm

-2)

Potential / V vs RHE

Fig1. (a)SEMimagesofelectrospunTiO2nanofiber, (b)Polarizationcurvesofpreparedcatalystsandcommercial IrblackmeasuredinO2-saturated0.5MH2SO4solutionatroomtemperaturewithrotationspeedof1600rpmandscanrateof5mV/sec


115

AbstractNo.121

PEM-Electrodedrying

F.Scheepersa,M.Staehlera,M.CarmoandW.Lehnerta,baForschungszentrumJuelichGmbH,InstituteofEnergyandClimateResearch,

IEK-3:ElectrochemicalProcessEngineering,52425Jülich,GermanybModellingintheElectrochemicalProcessEngineering,RWTHAachenUniversity,Germany

[email protected]

Summary.Anewmethodtoinvestigateselectivedryingprocessesofcatalystdispersionswassetup.Thevariationofdryingconditionsandcatalystdispersioncompositionanditsinfluenceonthelayerformationduringthemanufacturingofmembraneelectrodeassembliesisstudied.

Abstract.Theestablishmentofafullyrenewableenergysystemispredicatedontheuseofhydrogenasafuel.Polymerelectrolytemembrane(PEM-)waterelectrolyzersforhydrogengenerationand(PEM-)fuelcellsforitsreconversionwillbeessentialcomponentsofsuchasystem.Tobecomeeconomicallyfeasible,theircostshavetobereduceddrastically.Thequantityofexpensivematerialsutilizedfortheconstructionofcells,includingplatinum,iridiumortitaniummustbe reduced and overall efficiency increased. The efficiency of these devices is depending on the electrochemicalprocessesthattakeplaceintheelectrodesandisstronglyinfluencedbytheirstructure.Thestructurecanbeaffectedby controlling various steps in themanufacturing progress. Aside from the chemical composition of the wet coat(consisting of the supported catalyst, Nafion®, solvents and additives) the drying plays a significant role during theself-organizationprogressinthecatalystlayer.Therefore,thedryingaspectisoneofthemainfocusesofinterest.

Inthemanufactureofmembraneelectrodeassemblies(MEA)theusedcatalystdispersionsarecommonlybasedonamixtureoforganicsolvents.TomonitorthedryingprocessateststationwasdevelopedmeasuringtheevaporationofthesolventsselectivelyusingFT-IR-spectroscopyandisvalidatedtobeaccuratewithinafewpercent.Thedifferenceinthedryingratesforeachsolventresults inachangeofthecatalystdispersioncomposition.Thecompositioncanbedetermined as a function of time (fig. 1). Therefore, chemical and physical properties are varying over time.Consequentlythegeneratedcatalystlayerswilldifferwidelyifeitherthedryingconditions(e.g.temperature,overflowrate…)orthestartingcompositionareadjusted(fig.2).

Figure2:Same-sizedmicroscopicimagesresultingfromdifferentdryingcurves

Figure1:Dispersioncompositionasafunctionoftime


116

AbstractNo.122

Polymer functionalized carbon nanotubes as highly active bifunctional electrocatalysis for full water splitting

FatemehDavodi,aMohammadTavakkoli,aandTanjaKallioa

aDepartmentofChemistry,AaltoUniversity,SchoolofChemicalTechnology,P.O.Box16100,FI-00076Aalto,[email protected]

Summary.Wehavedevelopedafacileandscalablemethodforsynthesizingthebifunctionalnitrogenfunctionalizedcarbonnanotubes(NMWNTs)forfullwatersplitting.

Abstract.Amongdifferentmethods toproducehydrogenas the future cleanenergy carrier, electrochemicalwatersplitting is a promising straightforward method. However, efficient and low-cost electrocatalyst for hydrogen andoxygenevolutionreactions(HERandOER)oncathodeandanodeofanelectrochemicalelectrolyzerrespectivelyarerequired.Consequently,newalternativecatalystmaterialsmustbeintroducedsothatelectrochemicalelectrolyzerscanbeadopted.ForHERandOERefficientnon-noblemetalandmetalfreeelectrocatalystshavebeenintroducedrecently.

The unique structure and intrinsic properties of carbon nanotubes (CNTs) such as high-surface area, high-chemicalstability, and high electrical conductivity make them extremely attractive as catalyst supports for heterogeneouscatalysis.Thus,synthesisofcompositematerialsofCNTshasbeenselectedinthisstudyasapromisingapproachtofabricate efficient and low-cost electrocatalysts. Functionalization of CNTs with low-cost polymers is a novel andrelativelysimplemethodtofabricatemetalfreecatalystsforHERandOERinelectrochemicalwaterelectrolysis.Thefabricated composite materials, based on the combination of CNTs and polymers, have shown properties of theindividualcomponentswithsynergisticeffects[5].ThesemetalfreeelectrocatalystsshowcatalyticpropertiestowardbothHER in acidicmedia andOER in alkaline environment comparable to those of commercial noblemetal basedelectrocatalysts.ThisworkopensnewavenuesforthefunctionalizationofCNTwithpolymersinordertosynthesizenewcatalystmaterialsfortheelectrochemicalhydrogenproduction.


117

AbstractNo.123

Spinel-structuredmaterialsascatalystsupport/currentcollectormaterialsforPEMelectrolysiscells

FilippoFeninia,KentK.HansenaandMogensB.MogensenaaTechnicalUniversityofDenmark,DepartmentofEnergyConversionandStorage,Roskilde,Denmark

e-mail:[email protected]

Summary. Corrosion stability test conducted on different spinel-structured oxideswill be shown and the effect ofdifferent doping levels and types will be correlated to the stability of the materials, together with conductivitymeasurementshowingtheimpactofdopingonthematerialsproperties.

Abstract. PEM electrolysis cells can play an important role in the future energy scenario as efficient device forrenewably-producedintermittentenergyharvesting,duetotheirflexibilityandfastresponse[1].Coststillhindersawiderutilizationofthistechnology,notonlyduetohighpriceofthecatalystusedattheoxygenelectrodebutalsoduetocostlycomponentsandpoorcatalystutilizationduetolackofapropersupport.Ceramicmaterialscouldmatchthecharacteristicsrequiredfortheapplication,duetotheirinherentstabilitytowardfurtheroxidation,tuneableelectricalpropertiesandsurfacearea.Specifically,both theoreticalandexperimentalevidencehasbeen found thatCr-basedspinel-structuredmaterialscouldbetailoredtopossesshighconductivityatlowtemperaturebyproperdoping[2,3];moreover, thecorrosionstabilityof those issuggestedalsobythematerialsbeing found in thepassivation layerofstainlesssteels[4].

Differentformulationsofspinel-structuredmaterialswereinvestigated.Thematerialsweresynthesizedbysolidstateroute, calcined and pressed into pellets to prepare samples for the corrosion test. Harsh corrosion testing wasperformedonthematerialssimulatingcelloperationconditionsbyexposingthematerialstoanaqueousoxidizingandacidenvironmentat85°C.Themasslossafter24hoursofexposurewasnegligible,suggestingthematerialsbeingstableintheconditionsrequiredbytheapplication.Theeffectsofdifferentlevelsandtypeofdopingonelectricalandstabilitypropertieswillbeshown.Thedopingappearstoinfluencethecorrosionstabilityofthematerials,possiblybecauseofthe internal structural stress caused by the substituent ions, particularly at higher doping levels. ConductivitymeasurementsintheapplicationtemperaturerangewillbepresentedandcorrelatedtooccupanciesofAandBsitesdeterminedbyRietveld refinement (whereAandBare thetetrahedralandoctahedral sites respectively inaspinelstructurewithgeneralformulaAB2O4).[1]M.Carmo,D.L.Fritz,J.Mergel,D.Stolten,Internat.J.HydrogenEnergy,38,4901(2013).[2]Arpun,N.R.etal.Chem.Mater.26,4598–4604(2014)[3]Paudel,T.R.,Zakutayev,A.,Lany,S.,D’Avezac,M.&Zunger,A.Adv.Funct.Mater.21,4493–4501(2011)[4]LaFontaine,A.,Yen,H.W.,Felfer,P.J.,Ringer,S.P.&Cairney,J.M.,.Scr.Mater.99,1–4(2015)


118

AbstractNo.124

Hydrogenproductionfromshort-chainalcoholsusingpolymericprotonconductors

FoteiniSapountzia,MihalisN.Tsampasb,HansO.A.Fredrikssona,JoseM.GraciacandHans(J.W.)Niemantsverdrieta,caSynCat@DIFFER,SyngaschemBV,P.O.Box6336,5600HH,Eindhoven,TheNetherlands

bFOMInstituteDIFFER,DeZaale20,5612AJ,Eindhoven,TheNetherlandscSynCat@Beijing,SynfuelsChinaTechnologyCo.Ltd,1Leyuan2SouthStreet,SectionC,YanqiEconomic

DevelopmentArea,Beijing,101407,Chinaemail:[email protected]

Summary.Gasdiffusion electrodes interfaced topolymericH+ conductorswereused for producingH2 through theelectrolysis of C1-C3 alcohols and their mixtures. An alternative reactor design allowed us to quantify individualpotentiallosses.Theroleoftheanolytesolution’spHontheoverallperformancewasexamined.

Abstract. A promising approach for hydrogen production using polymeric electrolytes has emerged lately, namedalcoholelectrolysisorelectrochemicalreformingofalcohols.Thepowerdemandsforthisprocessaresignificantlylowercomparedtowaterelectrolysis,thusthistechnologycanofferremarkablyreducedoperationalcosts.

WeinvestigatedtheelectrolysisofC1-C3alcoholsandtheirmixturesusinganalternativereactordesign,appropriatefor fundamental investigations.Membrane-electrodeassembliesseparatedthetwochambersofanelectrochemicalreactor(fig.1a),filledwithaqueousalcoholandH2SO4solutions.Thehalf-reactionswhichtakeplaceuponpolarizationarethealcoholselectrooxidationattheanodeandthehydrogenevolutionatthecathode.TheaqueousphaseallowstheutilizationofastandardAg/AgClreferenceelectrodeformonitoringtheindividualoverpotentials(fig.1b).

Asshowninfigure1c,thedeconvolutionoftheoverpotentialcomponentsindicatedthattheoverallperformanceismainly (~75%)affectedby the sluggishanodic reaction (i.e.alcoholelectrooxidation).Proton transport through theelectrolyticmembranehasasmallercontributionwhilethecathodicoverpotentialisnegligibleinallcases.CellcurrentsunderstandardappliedpotentialswerefoundtodecreaseasthenumberofC-atomsinthealcoholincreases,duetothe formation of strongly adsorbed intermediates and to the need for breaking the C-C bond.Whenusing alcoholmixtures,theheaviestalcoholdictatesthecellperformance.ChangesinthepHoftheanolytesolutionwithintheacidicregimeaffecttheanodichalf-reaction,inawaythatthepresenceofionicagentsinthesolutionextendsthereactionzoneandthusincreasesreactionrates.

(a) (b) (c)

Figure1.(a)Schematicrepresentationofthereactor.(b)Thecorrespondingelectricalcircuits.(c)Effectofthecurrentonthetotalcelloverpotentialandontheanodic,cathodicandohmicoverpotentialsduringmethanolelectrolysis.

Acknowledgements:ThisprojecthasreceivedfundingfromtheEuropeanUnion’sHorizon2020researchandinnovationprogramme“CritCat”undergrantagreementNo686053andfromSynfuelsChinaTechnologyCo.Ltd.


119

AbstractNo.125

SinglecrystalstudiestoevaluatethestructuresensitivityoftheOxygenEvolutionReaction(OER)underacidicconditions

FrancescoBizzotto,YongchunFu,GustavK.H.WibergandMatthiasArenzDepartmentofChemistryandBiochemistry,UniversityofBern,Freiestrasse3,CH-3012,Bern,Switzerland

[email protected],weintroduceanewapproachtostudywell-definedmodelcatalystsfortheOERbasedonelectrochemistryandRamanspectroscopy.CombiningoxidestrippingwithRamanspectroscopy,wecorrelatethestructureofPtsinglecrystalswiththeirOERactivity.

Abstract.Fromfundamentalpointofview,theOxygenEvolutionReaction(OER)isthedecisiveprocessinelectrolysers.Theefficiencyofthedeviceismainlylimitedbythisreaction,whichexhibitsalargeoverpotentialonallknowncatalysts.Overthelastyearsmanyeffortshavebeenaddressedtodevelopmorestableandactivecatalysts.However,mostofthesestudiesinvolvednanostructuredcatalystsdepositedondifferenttypesofsupports,whilejustafewworkstriedtounderstandthefundamentalsofthisreaction.Suchinvestigationcanbeusedtoimproveactualcatalysts,buttheyarealsoanimportantlinkbetweentheoryandexperiment.OneofthemainissuesthatstillwaittobeexperimentallyexploredisthestructuresensitivityoftheOER.Usuallysuchstudiesaredonewithsinglecrystalelectrodesofdifferentsurfaceorientations.However,therearemanydrawbacksintheuseofthisapproachforstudyingtheOER.Themainchallengeisthatthesurfacelosesitsorderonceoverpotentialisdriventohighervaluesandmetaloxidesstarttoform.Thisprocessis inevitablesincetheoxideisanintermediateinthereactionmechanism,whilesurfacereorganisationcannot be easily avoided. Despite these intrinsic limitations, we have been able to retain structural informationdevelopinganinvestigationapproachbasedonelectrochemicalandspectroscopictechniques.ThisapproachallowedustoinvestigatethestructuresensitivityoftheOERonPtsinglecrystalsandhopefullysooncanbeappliedtomorerelevantsystems.


120

AbstractNo.126

ImpactofDynamicLoadfromRenewableEnergySourcesonPEMElectrolyzerLifetime

FransvanBerkela,ArenddeGroota,SandertenHoopenbaEnergyResearchCentreofTheNetherlandsECN,Westerduinweg3,1755LEPetten,TheNetherlands

bHydronEnergy,Walserij19D,2211SJNoordwijkerhout,[email protected]

Summary.Determining the lifetimeofelectrolysers is challenging,especiallyunderdynamic loadaswilloccurwithvarying energy supply by renewable energy sources. This paper discusses Accelerated Stress Testing proceduresallowingpredictionofdurabilityoftheelectrolysercomponentsunderrealisticdynamicmodeconditions.

Abstract.ThepaperdiscussesaPEMelectrolysertestprotocolforgaininginsightintothedegradationbehavioroftheelectrolyserspecificallyunderdynamicloadpatternsasmightoccurbyvaryingenergysupplyofrenewableenergy.PEMelectrolyserareabletoachieve40000hoursoflifetimeormore.However,thislifetimeliterallycomesatacost.Longlifetimescanonlybeachievedusingexpensivematerials.Degradationcanbelimitedbyusinghighcatalystloadings,thickermembranes,complexfabricationtechnologyfortheseparatorplate,etc.Buttheuseofthesematerialsaddsexcessively to thecostof theelectrolyserstack.Durabilityhas thusadouble impactontheelectrolysereconomics.Reduced lifetime increases the capital cost because of depreciation is doneover a shorter period of timebut alsobecauseoftheneedtogotomoreexpensivematerials.InadditionPEMfuelcelldevelopmenthasextensivelyshownthatdegradationmaybemuchquickerunder impactofrapid loadchanges,start-stopcyclesandoperationclosetoopencellvoltage.Althoughthereareanumberofimportantdifferencesbetweenfuelcellsandelectrolysers,durabilityneedstobeassessedbothunderfull-loadandundertransientandoff-designconditions.Inparticulariftheelectrolyserisusedtomanageavaryingsupplyofrenewableenergy,itwillbeoperatedundervaryingloads.Howthesewillvary,dependsontheapplication.

Determiningdurability is challenging,especiallywhendynamic loadpatternsareused. It is time-consuming todoasingle lifetimemeasurementand the timerequired todetermine the impactof severalvariables rapidlybecomesachallengingtask.The“holygrail”regardingtheissuelifetimeistobeabletoacceleratedegradationinsuchawaythatitallowspredictionofthedurabilityofcomponentsunderrealconditions(AcceleratedStressTesting(ASR)).Operatingatahighertemperature,ahigherimpuritylevelorhighercurrentdensitywillacceleratedegradation.Thereisaclearneedforthistypeoftesting,asillustratedbythesetofresearchprioritiesaspresentedbyHydrogenics.

InthispapersuggestionsforASRtestprotocolswillbegivenbasedonanextensivestudyondegradationmechanismsbothexperimentallyandfromliterature.


121

AbstractNo.127

ResearchandDemonstrationofSolidPolymerElectrolysisTechnologyinChina

SHIKun1a,WANGShubo2a,XIEXiaofeng3a,WANGChao4b,HOUHua5b,DENGYing6caTsinghuaUniversity,Beijing,China

bNorthUniversityofChina,Taiyuan,ChinacNorthChinaElectricPowerUniversity,Beijing,China

[email protected]

Summary.Solidpolymerelectrolyte(SPE)electrolysiswatertechnologyhasthecharacteristicsofhighefficiencyandhighpurity,andhasbecomeoneof theeffective technologies forpreparinghighpurityhydrogen. In this topic, theresearch status and commercial applications of SPE electrolysis technology in China is reviewed from four aspects:catalyst,membraneelectrodeassembly,separatorandmodelling.

Abstract.

Due to the increasingly prominent problemof environmental pollution, hydrogen as the cleanest energy has beenwidelyconcerned.SPEelectrolysiswatertechnologywithitslowenergyconsumptionandhighefficiencybecomeahottopicofconcern.

Since1987,ChinabegantheSPEelectrolysisofwatertechnologyresearch.PurificationEquipmentResearchInstituteofCSIC, Tsinghua University, Tianjin University, Beijing Institute of Technology, Dalian Institute of Chemical Physics,Chinese Academy of Sciences and other research institutions carried out a large number of catalysts, membraneelectrodeassemblyandotheraspectsofresearchwork.Afteryearsofhardwork,alarge-scaleSPEwaterelectrolysiswasproducedin2010.However,comparedwithalkalinewaterelectrolysis,thehighmanufacturingcostslimititspaceofindustrialization.Uptonow,therearefewexamplesoflarge-scaleapplicationofSPEelectrolysistechnologyinChina,thepotentialmarketisthattheresearchersdonotstoptheneedforfurtherresearch.

InordertoreducethecostofhydrogenproductionoftheSPE,thecostofelectricitymustfirstbereduced.Toachievethis, the SPE electrolysis water technology and renewable energy should be combined with the comprehensiveutilization of renewable energy. With the strong support of the Chinese government and the government of theKingdomofDenmark,ourresearchteam,PurificationEquipmentResearchInstituteofCSIC,TsinghuaUniversity,NorthUniversityofChina,NorthChinaElectricPowerUniversityandtheTechnicalUniversityofDenmarkjointlyaredoing:researchanddemonstrationofstoragesystemforhydrogenproductionbySPE,whichelectricityfromtheabandonedwind.Theresearchshouldstartfromthreeaspects,oneistopreparelow-cost,excellentperformanceandlonglifeoftheprotonexchangemembrane;thesecondisthedevelopmentofhighcatalyticactivityofnon-preciousmetalcatalyst;thirdistooptimizethecollector,separatorandhydrogensystemstructuredesign,furtherreduceenergyconsumptionandcost.

Acknowledgments This work is supported by the program of Sino-Danish Strategic Research Cooperation within Sustainable Energy,IntergovernmentalInternationalScientificandTechnologicalInnovationCooperationKeyProjects(2016YFE0102700).


122

AbstractNo.128

ProgressoftheEuropeanProjectEfficientCo-ElectrolyserforEfficientRenewableEnergyStorage-ECo

AnkeHagena,MariePetitjeanb,JulienVullietb,RegisAnghilantec,JanvanHerled,MarcTorrelle,AlbertTarancone,StefanDiethelmf,FrédéricMercierg,JacoboRubioFernandezh,andMarcoLindemann-Linoi

aDTUEnergy,bCEA,cEIFER,dEPFL,eIREC,fHTc,gENGIE,hENAGAS,[email protected]

Summary.TheECoProject aimsatutilizingelectricity from renewable sources forproductionof storagemedia viaelectrolysisofsteam&CO2inSOEC(SolidOxideElectrolysisCells).Thechallengeisapproachedfromcell,stack,andsystemlevel.

Abstract.TheconceptoftheECoprojectincludesthedevelopmentofimprovedSOECs,theinvestigationofdurabilityunderrealisticco-electrolysisoperatingconditions,thedesignofaplanttointegratetheco-electrolysiswithfluctuatingelectricity inputandcatalyticprocesses forhydrocarbonproduction, the transferofknowledge toand testofa co-electrolysissystemunderrealisticconditions,thedemonstrationoftheeconomicviabilityfortheoverallprocess,andalifecycleassessment.Highlightsfromthefirstprojectyearwillbepresented.

ImprovementoftheSOECperformanceisbasedonmicrostructuraltuning.Thiswasachievedspecificallyfortheoxygenelectrodebytwoapproaches:backbonemanufacturingandinfiltrationoftheLSCorLSCFphaseononeside,andparticlesizeoptimisationforscreenprintingoftheLSCF/CGOelectrodeontheother.

Forthemappingoftheperformanceanddurabilityofinitiallystate-of-the-artSOEC,acomprehensivetestmatrixwasidentified,whichisbasedonpreviousactivitiesofharmonisationofSOFC/SOECtestinginEurope,forexampletheEUSOCTESQA project, and was extended by the relevant parameters such as co-electrolysis and test under higherpressures.Thetestsarecombinedwithcomprehensivemicrostructuralpre-andpost-testanalysis.Furthermore,theresultsaresubstantiatedbyadetailedmodelthataccountsforelectrochemicalprocessesforagivenmicrostructure.

Systemmodels for theassessmentofdifferentpower-to-gasandpower-to-liquidscenarioswereestablished.Thesescenarios include different options for the SOEC co-electrolysis input (e.g., CO2 sources such as cement industry,electricity sources suchaswind turbines)andoutput (potential,desiredhydrocarbonproducts suchasmethaneormethanol).Theaimistoidentifythemostpromisingcasesandtobenchmarkthemwithstate-of-the-arttechnologiesandwithroutesviasteamelectrolysis.


123

AbstractNo.129

ComparativedegradationstudyofaNi-YSZsupportedSolidOxideFuelCellunderelectrolysisandco-electrolysisoperations

AzizNechache,RobertRuckdäschel,RémiCostaandGünterSchiller

GermanAerospaceCenter(DLR)InstituteofEngineeringThermodynamicsPfaffenwaldring38-40,D-70569Stuttgart

[email protected]

Summary.

anodesupportedsolidoxideelectrolysiscell

degradationstudyunderelectrolysisandco-electrolysisoperations

chronopotentiometryandelectrochemicalimpedancespectroscopy

Abstract. Production of renewable energies through the combination of different natural sources andpromisingtechnologiesisofcritical importance.Hydrogenproductionfromsteamwaterusingsolidoxideelectrolysis cells (SOEC) is part of this so called “energy mix”. In the present study, commercial anodesupportedsolidoxidefuelcells(SOFC)weretestedunderelectrolysisandco-electrolysisconditions.ThecellconsistedofNi-yttrium-stabilizedzirconia(Ni-YSZ)asfuelelectrode,gadolinium-dopedceria(GDC)/yttrium-stabilized zirconia (YSZ) as electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) asO2 electrode.Operationsunderelectrolysisandco-electrolysismodeslastedfor2500hoursand1500hours,respectively,withanappliedcurrentdensityof-1.0A/cm².Evolutionofthecelldegradationprofileswerefollowedwithtimethroughtheuseofchronopotentiometryandelectrochemicalimpedancespectroscopy(EIS).Thus,analysisofthepost-mortemcharacterizationbySEM/EDX,alongwiththeelectrochemicaltestingresults,aimsatdistinguishingthecellchangesspecificallyassociatedtodegradationunderco-electrolysisoperation.


124

AbstractNo.130

PerformanceanddegradationofaSOECstackwithdifferentairelectrodes

YulinYana*,CarolinE.Freya,PeterBatfalskyb,QingpingFanga,CaroleBabelotb,NorbertH.MenzleraandLudgerBluma

ForschungszentrumJülichGmbHaInstituteofEnergyandClimateResearch(IEK),

bCentralInstituteofEngineering,ElectronicsandAnalytics(ZEA)52425Jülich/Germany*[email protected]

Summary.A4-cellstackinF10-designfromForschungszentrumJülichGmbHwastestedinSOFCandSOECmode.Mid-termstationaryoperationwasconducted.TheperformanceandthedegradationbehaviorweremonitoredviaEISandDRTanalysiswasappliedtoimprovequalityandreliabilityoftheequivalentcircuitfitting.

Abstract.Theworldisrunningoutoffossilenergy.Thereforeitisessentialtoraisetheshareofrenewableenergyinpower production. Renewable energies cannot be regulated tomeet demand, somankind has to come upwith apossibilitytostoreenergy.Hydrogenisnotonlythefeedstockforthepetrochemicalindustryandammoniaproduction,butalsoanenvironmentallyfriendlyenergycarrier.Apromisingmethodtoproducehydrogenishightemperaturewaterelectrolysiswithsolidoxideelectrolysisstacks.

In this poster a 4-cell-SOEC stack in standard F10-design (see Figure 1.a) from Forschungszentrum Jülich GmbH ispresented.Thematerialsusedforthecellsarean8YSZelectrolytewithaGDCbarrierlayerandNi/8YSZassubstrateandfuelelectrode.Thestackisequippedwithtwodifferenttypesofairelectrodes,namelyLa0.6Sr0.4CoO3–δ(LSC)andLa0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF).

a)

b)

Figure 14: a) Jülich F10-design for two cells.[1] b) Stationary SOEC operation at 800°C, 50%humidifiedH2, -0.5A·cm

-1, 50% steamutilisation.

The performance of the stack wasmonitored both in SOFC and SOECmode at 700-800°C. A mid-term stationaryoperationat-0.5A·cm-1andsteamconversionof50%at800°Cwasconductedtoshowdurability(seeFigure1.b).Allcellsshowobviousdegradation,butlossofactivityforcellsequippedwithLSCishighercomparedtocellswithLSCFelectrodes.Electrochemical ImpedanceSpectroscopy (EIS)wasutilizedtostudytheelectrochemicalperformanceaswellasthedegradationbehaviourduringmid-termelectrolysis.Toimprovethequalityandreliabilityoftheequivalentcircuitfitting,aDistributionofRelaxationTimes(DRT)analysiswasapplied.Post-testanalysiswasusedtorevealreasonsfordecreasingactivityinelectrolysis.

[1] Q.Fang,L.Blum,R.Peters,M.Peksen,P.Batfalsky,D.Stolten,Int.J.ofHydrogenEnerg.2015,40,1128-1136.


125

AbstractNo.131

SynergiesbetweenSolidOxideElectrolyserCellsandCatalyticMethanisation

ChristianDannesboea,JohnBøgildHansen2aaAarhusUniversity–DepartmentofEngineering

bHaldorTopsøeA/[email protected]

Summary.This poster presents the first data froma pilot plant combining catalyticmethanisation and SolidOxideElectrolyser Cells. Carbon dioxide in biogas is upgraded to puremethane. Important synergies include excess heatrecovery,reuseofwastewaterandbiogaspretreatment.

Abstract. Catalytic methanisation is a highly exothermal reaction. The excess heat and generated water providesmultiplesynergieswhencoupledwithSolidOxideElectrolyzerCells.Thisstudyverifiesthesesynergiesina10Nm3/hpilotplantupgradingbiogasusinga50kWSOECashydrogensource.Datafrom1000productionhoursispresented.Thegasqualityproduced can replacenatural gas andprovides apromising future forhighly efficientpower-to-gasconversion.


126

AbstractNo.132

Techno-economicstudyofaReversibleSolidOxideCell(SOC)systemforindustrialhydrogenproductionandgridsupportapplications

DomenicoFerreroa,AndreaLanzinia,MassimoSantarellia,FedericoSmeacettob,OliverBormcandOliverPosdziechcaDepartmentofEnergy(DENERG)PolitecnicodiTorino,CorsoDucadegliAbruzzi,24,TurinItaly

bDepartmentofAppliedScienceandTechnology(DISAT)PolitecnicodiTorino,CorsoDucadegliAbruzzi24,TurinItalycSunfireGmbH,Gasanstaltstraße2,DresdenGermany

[email protected]

Summary. The effectiveness of arbitrage strategies for decreasing the cost of the hydrogen produced from SOECelectrolysisisinvestigatedthroughatechno-economicanalysisatthesystemlevel.Differentsolutionsforthereversibleoperationofasolidoxidecell(R-SOC)systeminagrid-connectedindustrialenvironmentareanalyzedanddiscussed.

Abstract.TheElectricalEnergyStorage(EES)intochemicalenergythroughreversibleSolidOxideCells(RSOCs)isoneofthemostpromisingsolutionsforlarge-scaleEESthatallowsthestorageofelectricalenergyintohydrogen–aflexiblemulti-purposeenergycarrier.Theproducedhydrogenproducedfromthehigh-temperatureelectrolysisplantisstoredeitherfordeferredelectricityproduction,thusoperatingtheSOCinfuelcellmode,oritusedasacommodityindifferentapplications (industryor automotive sectors, or even for the injection in thenatural gas grid). Especially, industrialhydrogenholdsahugemarketpotentialthatiscurrentlycoveredmostlybysteammethanereforming(SMR)(48%oftotaldemand[1]).

ToreachcompetitivecostswithhydrogenproductionbySMR,SOECsystemscouldexploittheflexibilityofreversiblesystems,whichcanalsoproduceelectricityfromthestoredhydrogen,orNGfromthegrid.Inthisway,itispossibletomaximizeallthepossibleintegrationsoftheSOECwiththeindustrialusers(especiallybyrecoveringavailableheatandsteamflows).

Thepresentworkaddressesthetechno-economicanalysisofdifferentoptionsfor increasingthecompetitivenessofSOEChydrogenproductionunderanarbitragestrategy.Infact,electricityisimportedfromthegriddependingonthehourlymarketprice.SOFCoperationisallowedbyusingeitherthestoredhydrogenornaturalgasfromthegrid.Thelevelizedcostoftheproducedhydrogenisevaluatedintheanalysisbytakingintoaccountthecostofplantequipment,maintenanceandelectricity/gassupply (netof therevenuesobtainedbysellingelectricity to thegrid).TheanalysisincludesrealistictechnologicalconstraintsoftheR-SOCsystem(i.e.,loadramprates,SOEC-SOFCswitchingtime)andappliesoptimizationprocedurestoidentifytheelectricitypriceforchangingtheoperationmodefromSOECtoSOFCwhichallowstominimizetheproductioncostofhydrogenondifferenttimescales(year,monthandweek).Theimpactof different electricity price andhydrogendemandprofiles on the levelized cost of hydrogen are investigated. ThepotentialforintegrationopportunitiesofRSOCsystemswithindustrialprocessesarefinallyassessed.

[1]FCHJU:StudyondevelopmentofwaterelectrolysisintheEU,FinalReport,p.4(2014)


127

AbstractNo.133

SolidoxideelectrolysisatForschungszentrumJülich

DominikSchäfera,QingpingFangaandLudgerBlumaaForschungszentrumJülichGmbH,InstituteofEnergyandClimateResearch,

Wilhelm-Johnen-Straße,D-52428Jülich,[email protected]

Summary. Solid oxide electrolysis for energy storage – the other side of a sustainable energy future. Status andperspectivesfromJülich’spointofview.

Abstract.Solidoxidefuelcells(SOFC)abletooperateinthereversedsolidoxideelectrolysiscellmode(SOEC)areaverypromisingtechnologyforbufferingsurplusesinenergysupply.Incaseofsteamelectrolysistheproducedhydrogengascouldbestoredandlaterconvertedbacktoelectricalpowerwhenneeded.Givenacheapheatsource(e.g.wasteheat),theSOECcanbeoperatedinanendothermalmodeandelectrical-to-hydrogenconversionefficienciesoforevenabove100%maybecomefeasible.Theco-electrolysisofsteamandcarbondioxideoffersevenmorepotentialforapplicationssincetheproducedsyngas(COandH2)canbeconvertedintoavarietyofusefulchemicalswhichmaynotonlybeusedforlaterpowergeneration.

ForSOECapplicationthereisnotyetasmuchknowledgeasfortheconventionalfuelcellmodeavailable.Thisappliesinparticular forcompletestacksandsystems,whichexcludetheapplicationofmanyanalytical techniques thatarereadily available for single cells, half cells or individual electrodes. Common expectations are that degradationmechanismsinSOECmodeandinparticularco-electrolysismodearedifferent.Accordingly,currentexperiencespointtowardsadecreasedoperationalstabilitythaninSOFCmode.

AnintroductionintothedegradationphenomenaspecifictotheSOECmodewillbegiven.Theaimistoapplytheexistingknowledge in designing, assembling, operating and characterizing anode supported SOFC stacks to extend thecorresponding knowledge for the SOEC and co-electrolysis modes. This contribution shall present and discuss thecurrentstateandtheongoingresearchactivitiesatForschungszentrumJülichconcerningthedevelopmentofSOECsbasedontheanode-supportedSOFCdesign,focusingontestingofwholestacks.


128

AbstractNo.134

3DprintedelectrolytesforSolidOxideElectrolyserdeviceswithcomplexhierarchicalgeometries

M.Torrell,E.Hernández,F.Baiutti,A.Morata,A.Tarancón

CataloniaInstituteforEnergyResearch(IREC),DepartmentofAdvancedMaterialsforEnergyJardinsdelesDonesdeNegre,1,08930SantAdriàdeBesòs,Barcelona,Spain

[email protected]

Summary.3DprintingtechnologyispresentedasanewmethodforthefabricationofcomplexstructuresforSolidOxideElectrolyserCells(SOEC)andmonolithicstacksbystereolithography(SLA)andYSZasprintingmaterial.

Abstract.SolidOxideElectrolysisCells(SOEC)devicesofferanefficienttechnologyforenergystoragethroughthepowertogasandpowertoliquidroutes.Theseroutesarepresentedasthemostefficientsolutionfortherenewableenergystorage,solvingthemismatchbetweenconsumptionanddemanddelayswithaclosetozerocarboncycle.SOECdevicesconvertsteaminhighlypurehydrogenoperatedunderelectrolysismodeormixturesofsteamandcarbondioxideinsyngas(CO+H2)underco-electrolysismode[1].Oneoftheproblemsofthesedevicesisthefabricationcostsduetothehighnumberofmanufacturingsteps[2].ThemainobjectiveofthepresentworkistofabricateYSZpiecesbySLAceramic3DprintingnewtechnologytobeusedasSOECelectrolyteswheredifferent3Dsurfacegeometriesareprinted.Theresultingcomplexgeometriesallowincreasingbetweentheactiveareapervolumeoftheelectrolyser.Atthesametime3Dprintingenablesmanufacturingmonolithic jointlessdevices thatease the fabricationprocessof theSOC stacks,avoidingthetypicalsealingproblemsofthestandardones.Italsopermitstodirectlylinkcatalyticreactorsforsyntheticfuelsfabrication.Theimprovementonthefabricationcostsofthesedevicesdirectlyresultsonamorecostefficientproducedor storedenergy [3]. In thepresentwork complexgeometriesof SLA3Dprintedelectrolyte, as theonespresentedinfigure1,areproposedandtestedasaSOECdevice.

Figures:Complex3DprintedgeometriesforSOEC electrolytes.

References.[1]ZhengY.etal.Areviewofhightemperatureco-electrolysisofH2OandCO2toproducesustainablefuelsusingsolidoxideelectrolysiscells(SOECs):advancedmaterialsandtechnology.Chem.Soc.Rev.,46(2017)1427-1463.[2]RouhollahD.etal.Three-DimensionalPrintingofMultifunctionalNanocomposites:ManufacturingTechniquesandApplications.Adv.Mater.28(2016)5794-5821.[3] Ruiz-Morales J.C. et al. Three dimensional printing of components and functional devices for energy andenvironmentalapplications.EnergyEnviron.Sci.,10(2017)846-859.AcknowledgementsThe authors want to acknowledge MINECO for the 3D Made project (ENE2016-74889-C4-1-R) that funded theacquisitionofpresentedresults.


129

AbstractNo.135

DevelopmentofSOECstacksatDTUEnergy

HenrikLundFrandsena,SørenHøjgaardJensena,LiHana,BelmaTalicaandPeterVangHendriksenaTechnicalUniversityofDenmark,DepartmentofEnergyConversionandStorage

[email protected]

Summary.DTUEnergyhasinitiatedthedevelopmentofSOECstacksforhands-on-experiencewiththechallengesofthestacktechnology.Theaimistodevelopdistinctstacks,whichaddressestheknownchallengesofthetechnology.Startingfromscratch(andnotfromanSOFCstack)someinterestingdesignchoicescanbemade.

Abstract.Inthispresentation,thedesignchoicesmadeforthefirstSOECstackdesignatDTUEnergyareshownandexplained. Focus has been on optimizing the cost both through choice of materials and processes, but mainly byincreasing the durability of the stacks. The intention is both to minimize the degradation of the electro-chemicalperformance,andtoimprovethemechanicalintegrityofthestacks.

Todecrease thedegradationof theNi containing cathode, this isexposed toa relativelydrymixtureof steamandhydrogentominimizetheNi-coarseningandmigrationoccurringathighpartialvapourpressures.Toavoidstarvationofthecell,thedrygasmixtureisoverblown(flowninhigherdegreethanstoichiometricallyneeded)byincreasingtheflowrateoverthecell.Thedrymixturecanbeachievedbypartiallyre-usingthefuelandaddingvapourforeachpass.

Herebythetemperatureofthestackcanalsobecontrolledbysupplyingconvective heat of a warmer vapour hydrogenmixture to balance theendothermicelectro-chemicalprocess.InSOFCstacksthisistypicallydoneby overblowing air over the air electrode. Thus, relatively larger gas-channelsareneededonthefuelsidebythistypeofoperation,ratherthanon the air side. Avoiding air-side overblowing also implies that theproducedoxygencanbeextractedandutilizedbysupplyingasmallunder-pressurewithoutdilutingitwithairoranothercarriergas.Theoxygenisinthecurrentdesignsuckedthroughthesidesperpendiculartotheflowdirectionofsteamandhydrogen,seeFigure15.Herebyacross-flowtypeofflow-fieldisachieved,butwiththethermaladvantagesofaco-flow,asthereisnogradientoftheoxygenpartialpressureontheanodeside(pureoxygen).

Theflowfielddoesthusprovideanalmostlinearthermalprofile,whichisbeneficial tominimizethemechanicalstresses.This is truebothforthestresses in the cell plane, and for the vertical stresses, which tends toinducelossofcontactbetweenthecellandtheinterconnect.Tofurtherenhancethedurabilityofthestackwithrespecttothisparticularfailuremode, flexible contact components have been introduced on eitherelectrode. Furthermore, on the oxygen side a noble in-situ reactionbondingcontactlayerhasbeenutilized.Thishasshowntobemechanicallysuperiortotheconventionalcontact layers.Usingtheseflexiblecontactlayers also enables the use of thin seals, as thick seals usually areemployed to accomodate the variations of the thickness of the layers,which naturally occurs in the production. Thinner seals are also anadvantagetominimizestheriskofmechanicalfailures.

Thecellsarefurthermoresealedinternallytoaframe,wherebyitcanbeavoidedtocutholesformanifolds inthecells. Internallycutholescanactaspointfromwhichcrackspropagatesduetotemperaturegradientsandflawsfromthecuttingprocess.Thisalsominimizestheleakageofthestacks,astheporouslayersarenotgoingallthewaytotheedgeofthestack.

Figure15StackcomponentsfromthefirstDTUEnergySOECstack.


130

AbstractNo.136

MeasurementofeffectivediffusionforNi/YSZmaterialusedforSOFC/SOECwithaWicke-KallenbachsetupandassessmentofconcentrationprofilesduringCO2-and

co-electrolysis.

JakobDragsbækDuhnab,AnkerDegnJensena,StigWedelaandChristianWixbaDTUChemicalEngineering

bHaldorTopsoeA/[email protected]

Summary.MeasurementoftheeffectivediffusionwithaWicke-Kallenbachsetuphasbeenconductedtodeterminetheeffectivediffusion for theNi/YSZelectrode.Basedon themeasurement, the resultingconcentrationprofilesduringelectrolysishasbeenmodelled.Especiallytheriskofcarbonformationhasbeeninvestigated.

Abstract.Inordertomodelthegasdiffusioninsolidoxidecells,theporosity,tortuosity,permeabilityandporediametermustbeknown.Theporosityandporesizedistributioncaneasilybemeasuredwithmercury intrusionporosimetry[1,2],thetortuositycanbecalculatedusingdataobtainedwithfocusedionbeam–scanningelectronmicroscopy(FIB–SEM)[3],orfromcorrelationswiththeporosity[4]and,thepermeabilitycanbemeasuredwithpermeametrywhereapressuredifferenceisusedtocauseaflow[5].However,indiffusionmodelsthetortuosityistypicallyusedasafittingparameterand includesnotonly theporeorientationeffects (measuredwithFIB-SEM),but also theeffectofnon-cylindricalporesandporeswithdeadends[6,7].Tofitthediffusionmodelsitisthereforenecessarytomeasuretheeffectivediffusion[2]orcalculateitfrompolarisationresistance[8].

Todirectlymeasuretheeffectivediffusionandsubsequentlycalculatethetortuosity,aWicke-Kallenbachdiffusioncellhasbeenused.TheeffectivediffusionwasmeasuredforfuelelectrodematerialsuppliedbyHaldorTopsoe.

UsinganextensionofapreviouslyreportedmodelforgasdiffusioninSOECcathodes[9],theconcentrationprofilesresultingfromtheeffectivediffusionmeasurementforCO2-andco-electrolysisarereported.TheconcentrationprofilesshowedthatthereisariskofcarbonformationviatheBoudouardreaction,duetohighconcentrationsofCO,iftheoperationconditionsarenotchosencarefully.

[1] D.Dong,X.Shao,X.Hu,K.Chen,K.Xie,L.Yu,Z.Ye,P.Yang,G.Parkinson,C.Z.Li,Int.J.HydrogenEnergy2016,41,44.

[2] R.E.Williford,L.a.Chick,G.D.Maupin,S.P.Simner,J.W.Stevenson,J.Electrochem.Soc.2003,150,8.

[3] J.R.Wilson,W.Kobsiriphat,R.Mendoza,H.-Y.Chen,J.M.Hiller,D.J.Miller,K.Thornton,P.W.Voorhees,S.B.Adler,S.A.Barnett,Nat.Mater.2006,5,7.

[4] W.Kong,Q.Zhang,X.Xu,D.Chen,Energies2015,8,12.

[5] E.Resch,MSc.Thesis,Queen’sUniversity,Kingston,Ontario,Canada,2008.

[6] M.F.L.Johnson,W.E.Stewart,J.Catal.1965,4,2.

[7] O.T.Chen,R.G.Rinker,Chem.Eng.Sci.1978,34.

[8] J.Aicart,M.Petitjean,J.Laurencin,L.Tallobre,L.Dessemond,Int.J.HydrogenEnergy2015,40,8.

[9] J.D.Duhn,A.D.Jensen,S.Wedel,C.Wix,inProc.12thEur.SOFCSOEForum,EuropeanFuelCellForum,2016,p.B0810.


131

AbstractNo.137

OrbitalPhysicsofActivePerovskitesforOxygenCatalysis

J.Gracia,1,2*R.Sharpe,2T.Lim,2Y.Jiao,2andJ.W.Niemantsverdriet1,21SynCat@DIFFER,SyngaschemBV,POBox6336,5600HHEindhoven(TheNetherlands)

2SynCat@Beijing,SynfuelsChinaTechnologyCo.,Ltd,Beijing-Huairou(P.R.China)*[email protected]

Summary.Inordertofindanexplanationforthedifferentperformanceofcomplexoxidesinoxygenelectrocatalyis,weperformabinitiocalculationstocorrelateactivityinrelationtothecorrespondingmagneticandelectronicstate.Wetrytounraveltheorbitalphysicsofthetransitionmetalsthatareparticularlyrelevanttooxygenelectro-catalysis.Abstract.CobaltitesandManganitesareamongthemostactivefamiliesofperovskitesinoxygencatalysis,ingeneral,with activities comparable to (and in some cases, greater than) noblemetals. Activity seems to be related to theparamagneticnatureofthe↑O=O↑molecule,andwiththepresenceofspecificexchangeinteractionsinthecatalyst.Forexample,thecatalyticactivityofcobaltitesincombustionreactionsisassociatedwiththreeconflictingelectronicstates:low-spin(LS)t2g

6eg0,high-spin(HS)t2g

4eg2andintermediate-spin(IS)t2g5eg

1;eachofthesestatescompetinginstability.[1]Theelectronicstructureoftheperovskitewilldependonthedominantorbitalconfiguration;ourrecentabinitiocalculationstrytounraveltheorbitalphysicsofthetransitionmetals,particularlyrelevantinthefundamentsofoxygenelectro-catalysis.[2]Our in-depth study of themagnetic structurewithinthe most active Cobaltites for Oxygen EvolutionReaction shows that conflicting orbital interactionsbetween localized spins helps in the extraction ofelectrons by ferromagnetic interactions: High SpinEntropy.[3][4] On the other hand, the electronicproperties of Manganites, good catalysts for theOxygen Reduction Reaction, agree with polariseddensity of states, ferromagnetic half-metals, with aCurie temperature above operation conditions: LowSpinEntropy.Theimplicationsofsuchobservationsarediscussed in termsofexchange interactions,becauseusuallyinthechemistryofparamagneticO2reactantsand products do not preserve spin, and effectivecatalysts can speed up the reactions if it is able toappropriatelyusethemagneticdegeneracies.Inagreementwiththeexperimentaldata,wenotethatinthemostactivecatalyststheelectronmobilityislinkedwithhighorlowentropyperelectron.Consequently,wediscussthecontributionoftheelectronicdegeneracies,entropy,tothekineticsofOERandORRonthebasisoftransitionstatetheory.WethusfindthatthemagneticphaseisactuallyanimportantfactorinthebestORRcatalysts.Ourfindingscanbeimmediatelyappliedinthefundamentalunderstandingofoxygenelectro-catalysis.References

[1] J.Gracia,M.Escuin,R.Mallada,N.Navascues,J.Santamaria,NanoEnergy2016,20,20–28.[2] F.M.Sapountzi,J.M.Gracia,C.J.(Kees-J.Weststrate,H.O.A.Fredriksson,J.W.(Hans)Niemantsverdriet,Prog.EnergyCombust.Sci.2017,58,1–35.[3] T.Lim,J.W.H.Niemantsverdriet,J.Gracia,ChemCatChem2016,8,2968–2974.[4] R.Sharpe,T.Lim,Y.Jiao,H.Niemantsverdriet,J.Gracia,ChemCatChem2016,DOI:10.1002/cctc.201600835.

Figure1.Roleofexchangeinteractionsinthedesign

principlesofOERandORRcatalysts.


132

AbstractNo.138

DeterminingthefractureenergyforoxygenelectrodeandcontactlayerinterfacesinSOECsstacks

LiHana,KawaiKwokb,LeneKnudsena,KjeldBøhmAndersena,BelmaTalica,TesfayeTadesseMollaa,MingChena,PeterVangHendriksena,andHenrikLundFrandsena

a DepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,RisøCampus,Roskilde,Denmarkb DepartmentofMechanicalandAerospaceEngineering,UniversityofCentralFlorida,Orlando,Florida32816,USA

[email protected]

Summary.Interfacefractureisakeyissueforreliablelong-termoperationofSOECstacks.Effectivebondingbetweeninterconnectsandelectrodes is required.Conventional interfacebondingstrengthbetweenoxygenelectrodes (LSC-CGO)andcontactlayers(LSC,LSM,LSC-LSM,LNF)wereinvestigatedinthisstudy,andabondingmethodusingCuMnfoamshowedsignificantimprovementcomparedwithothermethods.

Abstract.SOECstackshaveahighmarketvalue forconvertingelectricitydirectly intostorable fuelwithoneof thehighest efficiencies among other technologies. It shows a great promise for a highly efficient method for energyconversionandstorage.AbigchallengeforSOECstackistoachievehighdurabilityandstabilityunderlargeelectricalcurrents,gas/fuelcorrosions,andthermalcycles.Thisisbecauseinanoperationalstack,highconcentrationsofstressesare introducedbytemperaturegradientsandthermalexpansions.Forstressesperpendicular tothecellplanes, theweakestspotsinaSOECstackareattheinterfacesbetweenmetallicinterconnects,ceramiccontactlayers,andceramicoxygenelectrodes.

In this study, we systematically tested and analyzed the fracture energy for oxygen electrode and contact layerinterfacesinSOECstacks.ThetestscoveredpopularcontactlayermaterialsincludingLa0.6Sr0.4CoO3–δ(LSC),(La0.8Sr0.2)0.98MnO3-σ(LSM),LSC-LSM,andLaNi0.6Fe0.4O3(LNF),aswellasoxygenelectrodematerialLSC-CGO.AbondingmethodusingCuMnfoamwasadditionallyusedandinvestigated.

The fracture energy release ratewasmeasured bymodified 4-point bendingmethod using Charalambides type ofgeometry,wherethefractureenergywascalculatedfromtheload-displacementplateauatcrackpropagation.Alsothefracturemechanismswere investigatedbymicroscopy. Itwasfoundthatchemicalbondingandmassdiffusionhavesignificantinfluencetothefractureenergyoftheinterfaces.

A bonding method using CuMn foam showed an improved bonding strength to both the oxygen electrode andinterconnects,wherethesignificantlyhigherfractureenergywasobtained.Thisisexplainedbytheobservedeffectivechemicalreactionandbonding.


133

AbstractNo.139

Hightemperatureelectrolyserwithprotonconductingceramictubularcells

MateuszTaracha,b,NuriaBausáa,DavidCatalána,TrulsNorbycandJoséM.SerraaaInstitutodeTecnologíaQuímica(UniversidadPolitécnicadeValencia–ConsejoSuperiordeInvestigaciones

Científicas),Av.Naranjoss/n,E-46022Valencia(SPAIN)bAGHUniversityofScienceandTechnology,FacultyofEnergyandFuels,A.Mickiewicza30,30-059Krakow(POLAND)

cUiOUniversityofOslo,DepartmentofChemistry,FERMiO,Gaustadallèen21,NO-0349Oslo(NORWAY)*[email protected]

Summary.Multi-tubehigh temperature electrolyserwhich allowsmonitoring and controlling of individualmodulesatworkingconditionshasbeendesigned.ThetubularelectrolysiscellcomprisesaprotonconductingelectrolytewithLSM/BCZY2760/40vol.%anodecompositeinfiltratedwithPr-Ce50vol.%nanocatalysts.Abstract

HightemperatureelectrolysistechnologyoffershighconversionefficiencyofrenewableandpeakelectricitytoH2andmayincreaseperformancefurtherbyutilisingavailablesourcesofheatandsteamfromsolar,geothermal,ornuclearplant.Incontrarytosolidoxideelectrolysers(SOECs),whichoperateataround800°Candthehydrogenisproducedonthesteamfeedside,protonconductingelectrolysers(PCECs)generatepressurizeddryH2whatsignificantlyenhancestotalefficiency.

ThemainobjectiveofELECTRAprojectistodevelopanddemonstratescalablefabricationoftubularhightemperatureelectrolyser(HTE)cellswithprotonconductingelectrolyte.Inordertoproduce250Ln/hofH2(pressurizedat>10bara)from1kWofelectricalpower,multi-tubereactorhasbeendesigned.

ELECTRAutilisesanovelgenerictubularmoduleholdingsingle-endclosedtubes.Thetubularcellsaremountedwithpatentedsolutionallowingthentobeinserted,fastened,sealed,monitoredandcontrolledatworkingconditionsofindividualtubes, fromacoldaccessibleside.Highpressuresteamis fedtotheoutsideofeachtube,andpureH2 iscollected inside. The electrochemical performance and system durability have been studied by electrochemicalimpedance spectroscopy (EIS) and gas chromatography methods. The measurements were performed in thetemperaturerange800-600°Candupto30barofpressureofhumidifiedair(75%ofsteam).

Relatedtotheanodedevelopment,La0.8Sr0.2MnO3-d(LSM)compositematerialhasbeendepositedonproton-conductingBaCe0.2Zr0.7Y0.1O3-d (BCZY27) electrolyte and studied in symmetric cells to investigate the anodemicrostructure andelectrochemical performance. To enhance anode kinetic reaction, the LSM/BCZY27 60/40 vol.% composite wasinfiltratedwithPr-Ce50vol.%nanocatalysts.Finally, ELECTRA aims to demonstrate proof-of-concept CO2 and steam co-electrolysis, where compared to SOECs,pressurisedsteamandCO2arefedonseparatesidesofthecellinthePCECinco-ionicconductionmode,whichmaybeadvantageousforeconomicalsyngasproduction.

Acknowledgements

SpanishGovernment(SEV-2012-0267andENE2014-57651),PolishGovernment(DiamentowyD12013003243)andbytheEUFP7FuelCellsandHydrogen(FCH)JointTechnologyInitiative(JTI)underGAn°621244(“ELECTRA”).


134

AbstractNo.140

SpecificelectricalconductivityinsolidandmoltenCsH2PO4andCs2H2P2O7–apotentiallynewelectrolyteforwaterelectrolysisat~225-400°C

AlekseyV.Nikiforova,RolfW.BergbandNielsJ.Bjerrumc(pleaseunderlinepresenter)aDTUEnergy,TechnicalUniversityofDenmark

bDTUChemistry,[email protected]

Summary.ConductivityofsolidstateandmoltenCsH2PO4wascarefullyexaminedinthetemperatureinterval220-400°Cwith2°CstepsandunderitsownvaporpressureofH2Oinasealedampulesystem.Additionally,conductivitiesofmixturescomposedofCsH2PO4anddifferentcontentsofwaterandCsPO3wereexaminedandcomparedwithvaluescorrespondingtopureCsH2PO4.

Abstract.AnH-cellfabricatedfromquartzwasusedtoevaluatetheconductivityofsynthesizedCsH2PO4(CDP)anditsmixtureswithwaterorCsPO3.ThemeltingpointoftheCsH2PO4underitsownwatervaporpressurewasdeterminedtobe~345°C,whichwasprovedbydifferentialscanningcalorimetry(DSC),andRamanspectroscopy(RS)analysis,wherethelattertechniquegaveinformationonthedifferentstructuresofCDPat3temperatures:25,250and300.

Duringthemeltingprocess,thefollowingreactionstakeplaceinopenair[1-4]:

2CsH2PO4↔Cs2H2P2O7+H2O↔2/n(CsPO3)n+2H2O(n=1,2,3,….)(1)

MoltenCsH2PO4above347°Candunderitsownvaporpressurerepresentsaliquidwithahighconductivityof0.2Scm-

1,andincreasingfromthattemperatureitreachesvaluesabove0.25Scm-1at400°C.Ajumpintheconductivityfrombelow0.1Scm-1to0.25Scm-1opensnewperspectivesforpossibleapplicationsofthiselectrolyteinenergyconversionsystems at elevated temperatures. The conductivity data are given as polynomial functions of temperature andcomposition.TheresultsshowthatmoltenCDPhasasignificantpotentialaselectrolyteinintermediatetemperatureelectrolysissystems,essentiallyinthose,whereanexcessofwaterisunavoidable.X-raydiffraction(XRD),differentialscanningcalorimetry(DSC),andRamanspectroscopy(RS)analysiswereusedtoidentifyandcharacterisetheformedcompounds.Thefigureshowstheconductivityresultsobtained.Thephotoinsertshowstheampoulewiththefrozensaltsafterendofmeasurements.

1.W.BronowskaandA.Pietraszko,SolidStateCommunications,1990,76,293.

2.Boysen,ChemistryofMaterials,2003,15,727-736.

3.J.Otomoetal.,2005,JournalofAppliedElectrochemistry.,35865–70

4.C.E.Botezetal.,Thejournalofchemicalphysics,127,194701,pp.1-6,2007


135

AbstractNo.141

OxygenEvolutionReactionPerformanceofPrBaCo2O5+δandBa0.5Sr0.5Co0.8Fe0.2O2+δinCarbonatedElectrolyteforWaterElectrolysis

BaeJungKima,XiChenga,EmilianaFabbria,FrancescoBozzab,ThomasGrauleb,IvanoE.Castellic,d,NicolaMarzaric,JanRossmeisld,andThomasJ.Schmidta

aElectrochemistryLaboratory,PaulScherrerInstitut,5232VilligenPSI,SwitzerlandbLaboratoryforHighPerformanceCeramics,EMPA,SwissFederalLaboratoriesforMaterialsTestingandResearch,

8600Dübendorf,SwitzerlandcTheoryandSimulationofMaterials(THEOS),andNationalCentreforComputationalDesignandDiscoveryofNovel

Materials(MARVEL),EPFL,1015Lausanne,SwitzerlanddNano-ScienceCenter,DepartmentofChemistry,UniversityofCopenhagen,Universitetsparken5,Copenhagen2100

KbhØ,[email protected]

Summary.OERactivitiesandstabilitiesofreputableperovskiteoxides,PrBaCo2O5+δandBa0.5Sr0.5Co0.8Fe0.2O2+δ,areassessedunderaconditionthatbetterresemblepracticalapplicationoperation,whichtheelectrolyteisinaquasi-neutralpH.ObservationsareexplicatedinthermodynamicstandpointbasedonDFTcalculations.

Abstract.Developmentofenergy storage systems isabsolutelynecessary tomediate thevariablenatureofenergygeneration from renewable resources in the course of supplanting fossil-fuel based energy technologies. Thedevelopmentofwaterelectrolysistechnologieshasbeenthecentreofthespotlightowingtoitscapabilitytostorealargeamountofenergy.Thewatersplittingreactionwhichunderliestheperformanceofwaterelectrolysisrequireseffectiveelectrocatalyststofacilitateefficientoxygenevolutionreaction(OER),whichsuffersfromahighoverpotential.Amongcostviableelectrocatalysts,perovskiteoxidescomposedofabundanttransitionmetals,inparticularPrBaCo2O5+δandBa0.5Sr0.5Co0.8Fe0.2O2+δ,aregainingmuchattentionfortheirhighactivitiestowardOERinalkalinewaterelectrolyze.Up todate,however,only theirperformanceunderalkalineconditions (pH13–14)havebeenextensively studiedwithoutconsideringthepHchangestowardaneutralvalueuponthecontactofcarbondioxidefromtheatmosphere.In this investigation, we first compare and assess the OER activities of nano-scaled PrBaCo2O5+δ andBa0.5Sr0.5Co0.8Fe0.2O2+δ prepared via flame synthesis to thoseprepared via a conventional sol-gelmethod in alkalineconditions.Thereafter,weassess theOERactivitiesofelectrocatalystspreparedvia flamespraysynthesisunderanintentionallycarbonatedenvironmenttounderstandtheirelectrocatalyticfeaturesunderconditionsthathavebetterresemblance of a practical operation.We further elucidate on their electrocatalytic performanceswith DFT basedPourbaixdiagrams,whichprovidesfurtherinsightsintotheirthermodynamicstabilitiesinvaryingpHscale.Overall,wehighlight the importance of understanding OER activity under a practical operating condition and evaluating theelectrocatalyticperformanceonthebasisofthermodynamicstability.


136

AbstractNo.142

ThecatalysisoftheelectrolyticproductionofH2O2

ArnauVerdaguer-Casadevall,aRasmusFrydendal,aJanRossmeisl,bIbChorkendorffcandIfanE.L.StephenscaHPNowApS;bDepartmentofChemistry,UniversityofCopenhagen;

cDepartmentofPhysics,TechnicalUniversityofDenmark(DTU)[email protected]

Summary.AsurveyofelectrolyticH2O2production:acidversusbasisandmodelstudiesversusrealdevices.

Abstract.H2O2isavaluablecommoditychemical,withanannual global production exceeding 3 million tons. Atpresent, it is synthesised by the anthraquinone route, acomplex,batchprocess,conductedinlargescalefacilitiesfromH2andO2.H2O2istransportedhighconcentrations,although the end users often only need lowconcentrations. On-site electrolytic production of H2O2would mitigate current safety concerns related to itstransportationathighconcentrations.Moreover,itwouldbemoreinexpensivethantheanthraquinoneprocessandcircumvent the need for molecular H2. The viability ofelectrolyticH2O2productionisdependentonthecatalystatthecathode:notonlyshoulditexhibithighactivity,butalsohighselectivitytoH2O2overH2O.

We discovered a new set of electrocatalysts that showed an unprecedented combination of these two desiredproperties:alloysofPt,AgorPdwithHg.[1,2]Inourearlierpapers,wetestedthesecatalystsusingrotatingringdiskelectrode(RRDE)experimentsin0.1MHCLO4.[1,2]Inthecurrentcontribution,wealsotestthesecompoundsin0.1MKOH.We find that both the activity and stability follow vastly different trends from acid. We will also compareperformanceofthesecatalystsinaRRDEassemblytoarealdevicebasedonapolymerelectrolytemembraneelectrodeassembly.

Ourstudies incorporateelectrochemicalmeasurements,ultra-highvacuumbasedsurfacesciencemethods,electronmicroscopyanddensityfunctionaltheorycalculations.

[1]S.Siahrostami,A.Verdaguer-Casadevall,M.R.Karamad,D.Deiana,P.Malacrida,B.Wickman,M.Escudero-Escribano,E.A.Paoli,R.Frydendal,T.W.Hansen, I.Chorkendorff, I.E.L.Stephens, J.Rossmeisl,EnablingdirectH2O2productionthroughrationalelectrocatalystdesign,NatureMaterials,12(2013)1137–1143.

[2] A. Verdaguer-Casadevall, D. Deiana, M. Karamad, S. Siahrostami, P. Malacrida, T.W. Hansen, J. Rossmeisl, I.Chorkendorff, I.E.L.Stephens,Trends in theElectrochemicalSynthesisofH2O2:EnhancingActivityandSelectivitybyElectrocatalyticSiteEngineering,NanoLetters14(2014)1603-1608.

Left:Experimentalmeasurementof potential required forapartialcurrentdensityforH2O2productionof1mAcm-2,asafunctionofHOO*bindingenergy.Right:MassactivityofPd-Hg/CandPt-Hg/Cnanoparticles,relativetoAu/C.


137

AbstractNo.143

Bioreactorwithinsituwaterelectrolysisforproteinproduction

LauriNygrena,VesaRuuskanena,Juha-PekkaPitkänenb,PasiVainikkab,TuomoLindhaandJeroAholaaaLUTSchoolofEnergySystems,LappeenrantaUniversityofTechnology

[email protected]

Summary.Waterelectrolysis canbeapplied in cultivationofhydrogen-oxidizingbacteriabyperformingelectrolysisdirectly inabioreactor.ThebacteriausehydrogenasanenergysourceandaccumulateCO2 intobiomass.Bacterialbiomasshashighproteincontentanditcouldbeusedasaningredientinanimalfeedorhumanfood.

Abstract. Hydrogen-oxidizing bacteria (e.g. Cupriavidus necator, Rhodococcus opacus, and Hydrogenobacterthermophilus)arecapableofautotrophicgrowthbyusinghydrogenasanelectrondonorandoxygenasanelectronacceptortofixcarbondioxidetobuilduptheirbiomass[1].Hydrogenandoxygencanbesuppliedforthebacteriabyperformingelectrolysisdirectly in thebioreactor,wherethebacteriaarecultivated. Insituwaterelectrolysisallowsefficientsubstrateutilizationbythebacteria,duetobettermasstransferofgastoaqueoussolution,thaninthecaseofexternalgassupply.Alsoflammablemixturesinthereactorheadspacecanbeavoided.InadditiontoH2andO2,CO2andnutrientsneededforgrowtharesuppliedtothereactor.

Bacterialbiomasshashighproteincontent(50–83%),anditcanbeusedasaningredientinhumanandanimalnutrition.Anelectricity-to-biomassefficiencyof54%hasbeenachievedbyapplyingdirectelectrolysis inabioreactor,whichwouldcorrespondtoapproximately10%solar-to-biomassefficiency(assuming18%efficiencyforphotovoltaics)[2].Forcomparison,theannualaverageefficiencyofcropsdonottypicallyexceed1%,andefficienciesduringthegrowingseasonscanreachonly3.5–4.3%[3].Bacteriahavealsoveryfastgrowthrate.Theirbiomassdoublingtimeistypically20-120minutes,whilee.g.soybeanhasdoublingtime1–2weeks.

Duetohighconversionefficiencyandfastgrowth,bacterialproteinproductionrequiressignificantlylesswaterandlandarea compared to the conventional protein sources. By applying direct air capture (DAC) of CO2 byadsorption/desorptionprocess,bacterialproteincanbeproducedbasicallyonlyfromelectricity,airwaterandsomenutrients,makingtheproductionveryindependentonplaceandclimate.Theconceptisstillinresearchstage,butinthefuture,itmayprovideasolutiontoenvironmentalimpactsofconventionalagriculture,suchasgreenhousegases,fresh water use, land use, and pollution caused by fertilizers and pesticides. Optimization of electrode materials,cultivationmediumandconditions,bioreactorconstruction,andprocessmodelingandcontrolareunderresearchbytheauthors.

[1]Aragno,M.,1998.Theaerobic,hydrogen-oxidizing(knallgas)bacteria.In:Techniquesinmicrobialecology.EditorsR.S.Burlage,R.Atlas,D.Stahl,G.Geesey,G.Sayler.OxfordUniversityPress,NewYork.

[2] Liu, C., Colón,B. C., Ziesack,M., Silver, P.A.,Nocera,D.G., 2016.Water splitting-biosynthetic systemwithCO2reductionefficienciesexceedingphotosynthesis.Science,vol.352,pp.1210–1213.

[3]Blankenship,R.E.,etal.,2011.Comparingphotosyntheticandphotovoltaicefficienciesandrecognizingthepotentialforimprovement.Science,vol.332,pp.805–809.


138

AbstractNo.201

DevelopmentofoxygenevolutionelectrocatalystsandelectrodesforHighTemperatureandPressureAlkalineElectrolysisCells(HTP-AEC)

JensQAdolphsena*,BhaskarReddySudireddya,VanesaGila,ChristodoulosChatzichristodouloua•aDTU,DepartmentofEnergyConversionandStorage

*[email protected]; •[email protected]

Summary.Anewalkalineelectrolysiscellconcept,HTP-AEC,withcellsoperatedat~200°Cand~45barinconcentratedKOH(45wt%),offersthepotentialofa10-foldincreaseincurrentdensityandofincreasingtheelectricalefficiency.

Abstract.Anewalkalineelectrolysiscellconceptwithcellsoperatedathightemperature(~200°C)andpressure(~45bar)inconcentratedKOH(45wt%),offersthepotentialofa10-foldincreaseincurrentdensitywhileincreasingthecellefficiencyaswell.Onechallengeliesinidentifyingceramicmaterials,whichareelectrocatalyticallyactivefortheoxygenevolutionreactionandchemicallystableunderoperation.Perovskitetypematerials,consistingofLa,Ni(andFe),withcompositions LaNi0.6Fe0.4O3,La0.97Ni0.6Fe0.4O3, La2Ni0.9Fe0.1O4andamultiphasematerial containing LaNiO3, havebeenidentified as potential candidates for the oxygen electrode. The compositions are LaNi0.6Fe0.4O3, La0.97Ni0.6Fe0.4O3,La2Ni0.9Fe0.1O4andamultiphasematerialcontainingLaNiO3.TheirelectrocatalyticactivityhasbeenmeasuredatSTPin1MKOHshowingsimilarperformanceasstate-of-the-artelectrocatalysts,suchasIrOx,Ni1-yFeyOx,andPrBaCo2O5+x.Theirchemicalstability,testedat200°C,15barpressurein45wt%KOH,wasfoundtobeinadequate.LaNi0.6Fe0.4O3wasselectedforprocessingporousoxygenelectrodes,aimingtorevealthemicrostructure-performancecorrelationsthatwillleadtoelectrodeoptimization.Amicrostructurallyoptimizedoxygenelectrodewillbeintegratedintoouralkalineelectrolysiscellconcept.Theproject,hence,aimsatdemonstratingthefeasibilityofthiscellconceptbyfullcelltestingat5x5cm2cellsize.

References

[1]C.C.L.McCrory,S.Jung,J.C.Peters,T.F.Jaramilllo,J.Am.Chem.Soc.135(16977-16987),2013

[2]L.Trotochaud,J.K.Ranney,K.N.Williams,S.W.Boettcher,J.Am.ChemSoc.134(17253-17261),2012

[3]A.Grimaud,K.J.May,C.E.Carlton,Y-L.Lee,M.Risch,W.T.Hong,J.Zhou,Y.Shao-Horn,Nat.Commun.4(2439-2445),2013

Material b(V/dec) η(V)@10mA/cm2

LaNiO3 0.079 0.38

La0.97

NiO3 0.092 0.44

LaNi0.6Fe

0.4O

3 0.12 0.44

La0.97Ni0.6Fe0.4O3 0.10 0.45

La2Ni

0.9Fe

0.1O

4 0.077 0.40

IrOx[1] - 0.32

Ni0.9Fe

0.1O

x[2] 0.030 0.34

PrBaCo2O

5+x[3] ~0.07 ~0.38


139

AbstractNo.202

Hydrogenproductionfromphotovoltaicvia“zerogap”alkalineelectrolysis

JirinaPolakovaa,AlesDoucekaandPetrHajekaaHydrogenTechnologiesDepartment,UJVRez,Hlavni130,Rez,25068Husinec,CzechRepublic

e-mail:[email protected]

Summary.Thewaterelectrolysisconnectedwiththerenewablyenergysourcesrepresentsapromisingwayofhydrogenproduction without CO2 footprint. However, currently used alkaline electrolyzers are not suitable for intermittentoperation required for this type of application. The concept of zero-gap alkaline electrolysis with ion conductionmembraneappearssuitableforthisapplication.

Abstract.Theprocessofalkalinewaterelectrolysisisoneofthecandidatetechnologiesforproducinghydrogenonalargescalefromrenewableenergy,becauseitdoesnotrequireapplicationofpreciousmetals,likeplatinum,rutheniumetc.,ascomparedtoprotonexchangemembraneelectrolysis.However,thissystemhaslimitedabilitytorespondtofluctuationsinelectricalpower,whichiscommonlyrequiredinconjunctionwithrenewableenergysources.Thepaperdealswiththedesignofaninnovativeconceptofalkalineelectrolysiswhichisabletoovercomethisrestriction.Thedesignoftheelectrolyzerisbasedonazerogapbipolarcellconstruction.Forachievingthistargetitwasnecessarytodevelopanon-platinumelectrocatalyst,whichisnecessarytoaccelerateelectrodereactions,andanalkalinepolymermaterial,whichisabletofulfiltheroleofananionconductingelectrolyte.Also,structureandgeometryoftheindividualelectrolyticcellweredesignedandoptimized.

Thefinalelectrolyticstackhastheelectricalpowerinputof1kWandoperatingconditionswere60°C,4bargand10- 30 wt% solution of KOH as electrolyte. The cells weremade of hydroxide ion conductingmembranes based onpolyethylene, and nickel foam as electrodes with different electrocatalysts for both anode and cathode side. Thedifferent typesofmembraneswere tested. In general, theperformanceof laboratorymembranewas similar toanindustrymembraneat30wt%KOHelectrolyte;nevertheless, at10wt%KOHelectrolyte the laboratorymembraneachievedconsiderablyhigherperformanceincomparisonwiththeindustrymembrane.Theconceptwasverifiedinrealoperational conditions; the results are shown in figure 1. The alkaline electrolyzer responds very quickly to thefluctuations in electric power supplied by a photovoltaic plant. The suggested design of electrolyzer is suitable forproductionofhydrogenfromrenewablesources.

Fig.1Realperformanceofalkalineelectrolyzeroperatedaccordingtothepowerofphotovoltaicpanelsduringtheday

Acknowledgement.FinancialsupportofthisresearchbytheMinistryofIndustryandTradeoftheCzechRepublicunderprojectNo.FV10529isgratefullyacknowledged.

0

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]

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PhotovoltaicplantElectrolyzer


140

AbstractNo.203

Mathematicalmodelandexperimentalvalidationofa15-kWalkalineelectrolyzer

MónicaSáncheza,ErnestoAmoresa,LourdesRodríguezb,CarmenClemente-JulcaCentroNacionaldelHidrógeno,ProlongaciónFernandoElSantos/n,13500Puertollano,CiudadReal

bUniversidadEuropeadeMadrid,Tajos/n,UrbanizaciónElBosque,28670VillaviciosadeOdón,MadridcDpto.EnergíayCombustibles,ETSIMinasyEnergía,UniversidadPolitécnicadeMadrid,RíosRosas21,28003Madrid

[email protected]

Summary.Theobjectiveofthisworkistodevelopasemi-empiricalmathematicalmodelthatpredictsthevoltageandtheFaradayefficiencyofanelectrolyzerasafunctionofthecurrent.Thismodelhasbeenfittedwiththeexperimentaldataobtainedwitha15kWalkalineelectrolyzeratdifferenttemperatures,pressuresandelectrolyteconcentrations.

Abstract.Theelectrochemical behaviour of an electrolyzer canbemodelledusing a semi-empirical current-voltagemodel.Oneofthemostwidelyusedmodels is theoneproposedbyUlleberg[1],whichdescribesthevoltageofanelectrolyzeraccordingtotheparameters“s”(V)and“t”(m2/A)relatedtoactivationoverpotentialsand“r”(Ω·m2)fortheohmicoverpotentials.However,inthismodeltheparametersonlydependonthetemperature(T).Inordertoobtainawidermodel, theequationhasbeenmodified to includepressure (p) andelectrolyte concentration (M). For thispurpose, two additional parameters havebeen incorporated in themodel: “j” and “d” (Ω·m2)which represent thevariationintheohmicoverpotentialsaccordingtotheelectrolyteconcentrationandpressure,respectively.

𝑈 = 𝑈456 + 𝑠 · 𝑙𝑜𝑔 𝑡 · 𝑖 + 1 + 𝑟 + 𝑗 + 𝑑 · 𝑖 ⟹

𝑈 = 𝑈456 + 𝑠 · 𝑙𝑜𝑔 𝑡E + 𝑡- · 𝑇FE + 𝑡G · 𝑇F- 𝑖 + 1 + 𝑟E + 𝑟- · 𝑇 + 𝑗E + 𝑗- · 𝑀 + 𝑗G · 𝑀- + 𝑑E + 𝑑- · 𝑝 · 𝑖

RegardingFaradayefficiency,ithasbeenmodelledusingtheequationproposedin[1],includingalinearrelationfortemperature(“f1”,“f2”).Thepressureandelectrolyteconcentrationhavenotbeenincludedduetoitsslightinfluence:

𝜂K = 𝑓E + 𝑖- FE · 𝑖- · 𝑓- ⟹ 𝜂K = 𝑓EE + 𝑓EE · 𝑇 + 𝑖- FE · 𝑖- · 𝑓-E + 𝑓-- · 𝑇

Figure1.15-kWelectrolysistestbench

A15-kWalkalineelectrolysistestbenchdevelopedbyCNH2[2]hasbeenusedforcarryingouttheexperimentaltests(Figure1).Forthispurpose,a 12-bipolar cell stack of 1000 cm2 surface area with a nominalproductionrateof2Nm3/hhydrogen(@400A)hasbeencharacterizedat different temperatures (55, 65, 75 °C), pressures (5, 7, 9 bar) andelectrolyteconcentrations(28,35,42%w/wKOH).Ineachoftheseteststhepolarizationcurve,thepurityofthegasesproducedandtheFaradayefficiencyhavebeenstudied.Astandardprocedurehasbeenfollowedtoensuretherepeatabilityandreproducibilityoftheexperimentaldata.

Themodelconstantshavebeencalculatedbymeansofanon-linearregressionusingMATLAB,accordingtoapreviouslyestablished procedure [3]. To do this, the experimental data obtained for the polarization curve and the Faradayefficiencyhavebeenused.Thepredictionaccuracyofthemodelcanbeverifiedbycomparingsimulatedandmeasuredvaluesforthepolarizationcurvesatdifferenttemperatures,pressuresandelectrolyteconcentrations(seeFigure2).AlsotheRMSerrorhasbeenevaluatedwitharesultof6.18mV(voltagecell)and0.53%(Faradayefficiency).

Figure2.Calculated(line)vs.measured(dot)voltageatdifferenttemperatures(a),pressures(b)andelectrolyteconcentrations(c)

[1]Int.J.HydrogenEnergy200328pp.21;[2]M.Sánchezetal.Iberconappice.Barcelona2014;[3]Int.J.HydrogenEnergy201439(25)pp.13063


141

AbstractNo.204

ActivityofplasmavapourdepositedPtxNiyAlzasanodeelectrocatalystfor(membraneless)alkalinewaterelectrolysis

RJKrieka,HKKishinkwaa,MGillespiebandAFalchaaElectrochemistryforEnergy&EnvironmentGroup(EEE),ResearchFocusArea:ChemicalResourceBeneficiation

(CRB),PrivateBagX6001,North-WestUniversity,2520,Potchefstroom,SouthAfricabDemcoTECHEngineering,1HighStreet,ModdercrestOfficePark,Johannesburg,SouthAfrica

[email protected]

Summary.Pt9Ni56Al35,intheformofaplasmavapourdeposited(PVD)thinfilm,greatlyenhancestheoxygenevolutionreaction(OER)inalkalinemediaonbothalaboratoryscale(depositedontoglassycarbondiskinserts)aswellasonapilotscalethatconsistsofadivergentelectrodeflow-through(DEFTTM)membranelesselectrolyser.

Abstract. The two predominant water electrolysis technologies are alkaline electrolysis (AEL) and acid or protonexchangemembraneelectrolysis (PEMEL).AEL is themoremature technologyand is thecurrentstandard for largeindustrialscaleproductionofhydrogen(intheMWrange).Itisafairlyrobusttechnologyandcommonlymakesuseofnickel coated steel electrodes.AEL technology,however, suffers from lowcurrentdensities anda limitedability torespondtofluctuationsinelectricalinput,whichiscrucialwhentryingtointegraterenewablessuchaswindandsolar.PEMEL, on the other hand, can operate at higher current densities, but it comes at a huge cost as the electrodespredominantlycontainnoblemetalssuchasplatinum,iridiumandruthenium.ItisasaresultofthisfactthatPEMELdoesnotoperateintheMWrangeandispredominantlyemployedinthedecentralisedonsiteproductionofhydrogen,suchashydrogenrefuellingstations.Costeffectiveandhigh(er)efficiencyAELwatersplittingtechnologyisthereforeneededthatoperatesathigh(er)currentdensities,butwithouthighnoblemetalcontent.

WhilethecurrentOERelectrocatalystsconsistofpuremetalsuchasNi,orexoticmaterialssuchasRuO2and/orIrO2,ournewlydevelopedOERelectrocatalystconsistsofathinmetalfilm,intheformofhighlyactivePt9Ni56Al35,whichisco-depositedontotheelectrodebymeansofplasmavapourdeposition.OnglassycarbondiskinsertsPt9Ni56Al35,aswellasotherPtxNiyAlz ratios,outperformpureNi,PtandNiyAlz (Figure1).OnapilotDEFT

TMmembranelessalkalinewaterelectrolysisfacilityPt9Ni56Al35increasescurrentdensitybetween50and100%(Figure2).

Figure1 Linear polarisation scans of PVD electro-

catalystsonglassycarbon(0.1MKOH)Figure2 CurrentdensitiesonaDEFTTMmembraneless

electrolyserfordifferentelectrocatalysts


142

AbstractNo.205

Small-scalesystemsforalkalinewaterelectrolysisMeikeV.F.Heinz1,WenboJu1,DariuszBurnat1,LorenzoPusterla1,CorsinBattaglia1,UlrichF.Vogt1

1Empa,SwissFederalLaboratoriesforMaterialScienceandTechnology,MaterialsforEnergyConversion,CH-8600Dübendorf

2FacultyofEnvironmentandNaturalResources,Crystallography,Albert-Ludwigs-University,[email protected]

Summary.Duetothe increasingamountofrenewableelectricity,waterelectrolysisattractsaccretive interestasanenvironmentalfriendlyhydrogenproductiontechnology.Besidespolymerelectrolytemembraneelectrolysis(PEME),alkalineelectrolysis(AE)isofhighinterestformegawattsystemsduetoitsrobustqualityandlong-lifeexperience.

Abstract.Inordertomakealkalineelectrolysismoreattractive,theenergyconsumptionforwatersplittinginalkalineelectrolysishastobereducedandthepowerdensityincreased.Whiletheelectrocatalyticactivityofelectrodematerialsisfrequentlystudiedinthiscontext,systemparameterslikeoperationtemperature,workingpressure,celldesignandprocessparameters like electrolyte flowor gasbubblemanagement are alsoof high importance for improving theelectrolyser efficiency. Experimental studies on such parameters are scarce, as laboratory equipment for realisticalkalineelectrolysisconditionsishardlyavailable.

For these reasons we have acquired two different small-scale water electrolysis systems: A lab-pilot electrolyserVOLTIANA,basedonastackof5to10cellswith500-1000cm2activearea,andacustom-madelaboratoryelectrolyserElectraIV,basedononecellof20cm2.Wediscusshowtheseelectrolyserscanbeusedformaterialtestingandprocessoptimisationofboth,systempropertiesandfundamentalstudies.Wepresentresultsapplyingstandardelectrodesandcost-effective composite diaphragms. The diaphragms are prepared in-house by a phase inversion process and arecomposedofpolysulfone(PSF)asbindercombinedwithbarite(BaSO4)asparticlefiller.

Lab-pilotelectrolyzerVOLTIANA:Electrolyzercabinet(a),7cellstack(b),andsinglecelldesign(c).

LaboratoryelectrolyserElectraIVwithcellcompartment.


143

AbstractNo.206

Newseparatorconceptsforaradicalimprovementofthegasqualityinalkalinewaterelectrolysis(AWE)

WimDoyen1a,YolandaAlvarez2a

Keywords:AdvancedAlkalineWaterElectrolysis,AWE,Hydrogengeneration,Technology,MaterialaVitoNV,Boeretang200,B-2400Mol,Belgium

[email protected]&[email protected]

Summary.Poorgasqualityat lowcurrentdensityandatveryhighpressure isamajordrawbackofAlkalineWaterElectrolysis(AWE).Thislimitationcanbesubstantiallymitigatedwithanewseparatormembraneconceptespeciallytailoredforthispurpose.

Abstract.AdvancedAlkalineWaterElectrolysistechnology(AWE)usingthinseparatorhasalotofadvantagesoverPEMelectrolysistechnology:itiswellestablished,withsystemsuptoMWscalealreadycommercialanditisthecheapesttechnology.However,theAWEtechnologysuffersfrompoorgasqualityatacurrentdensitybelow0.2A/cm²and/oratveryhighpressure(above50bar).

Vitoisdevelopingnewseparatorconceptstosolvethisdisadvantage.Differentapproachesarebeingused.Oneofthenewseparatormembraneconceptsrecentlydevelopedisthee-by-passseparator. Itfeaturesaninternalelectrolytecirculation(anelectrolytebypass).

Figure1:cross-sectionofthedouble-layer“e-bypass”separator

Thise-bypassseparatorisconstructedaroundadedicated3D-textilestructure(aweft-typeofPPSspacer-fabric),whichisusedinthesametimeasasupportstructureandasaspacermaterial.ThisPPSspacer-fabriciscoatedonitsbothsideswith a Zirfon® separator layer, resulting in a “double-layer separator”which comprises the aforementionedinternalelectrolytechannel.Theinternalchannelformsathirdcompartmentintheelectrolyserbetweentheanolyteandthecatholytecompartments.Withthisseparatorconceptandnovelcelldesign(adaptedtoimprovemasstransfer)HTOvaluesbelow0.1%havebeenachievedat0.150A/cm²(1)vs.0.8%HTOforstate-of-the-artAWE.

Otherseparatorconceptsarebeingengineered,alsotargetingHTOvaluesbelow0.8%..Thepresentationwillgiveanoverview of the potential for improvement of gas quality with these novel separator concepts, as well as theirlimitations.Preliminaryresultsandresearchprospectswillbediscussedaswell.

Acknowledgements:ThisworkhasbeenpartlycarriedoutwithintheprojectElyntegration.ThisprojecthasreceivedfundingfromtheFuelCellsandHydrogen2JointUndertakingundergrantagreementNo671458.ThisJointUndertakingreceivessupport fromtheEuropeanUnion’sHorizon2020researchand innovationprogrammeandSpain,Belgium,Germany,Switzerland.TheresearchleadingtotheseresultshasreceivedfundingfromtheEuropeanUnion’sSeventhFramework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grantagreementn°[278732],projectRESelyser.TheauthorsgratefullyacknowledgefruitfuldiscussionswithElyntegrationprojectpartners:FHA(Spain),IHT(Switzerland),FraunhoferIFAM(Germany),INYCOM(Spain),IAEW(Germany);andwithRESelyserprojectpartners:DLR,HydrogenicsEurope(Belgium)andDTU(Denmark).1PublicfinalreportRESelyser,http://www.fch.europa.eu/project/hydrogen-res-pressurised-alkaline-electrolyser-high-efficiency-and-wide-operating-range


144

AbstractNo.207

ControlandenergyefficiencyofalkalineandPEMwaterelectrolyzersinrenewableenergysystems

JoonasKoponena,VesaRuuskanena,AnttiKosonena,MarkkuNiemeläa,andJeroAholaaaLUTSchoolofEnergySystems,LappeenrantaUniversityofTechnology,Finland

[email protected]

Summary.WaterelectrolyzersrequireDCpowerandtheiroperationdependsonelectricconditioning.Experimentalsetupincludingasmall-scalealkalineandPEMelectrolyzer isbuilt inorderto identifyfactorsfromtheviewpointofpowerelectronicsaffectingthespecificenergyconsumptionofthesetwowaterelectrolysisprocesses.

Abstract.Inordertoreachanetzero-emissionsociety,thewholeenergysystem—includingelectricity,transportation,anddirectindustrialfueluse—hastoberestructured.ThiswouldpracticallyrequireCO2freepowergeneration,bridgesbetween different areas of energy systems, and efficient means of energy storage. To support the global energytransition,renewablehydrogenandrecycledCO2arerequired.Therefore,thetechnicalandeconomicperformanceofwaterelectrolysisprocesseswillbeinakeyrole.

TheFaradayefficiencyisdeterminedasaratiooftheactualandidealhydrogenproductionrates;theidealhydrogenproductionisproportionaltothemeanofthecurrentsuppliedtotheelectrodes,whiletheactualhydrogenproductionratemight be lower due to process inefficiencies. The Faraday efficiencymay decrease notably from unity due tohydrogengascrossoverintotheanodecompartment,straycurrents,orreductionintheactivecellareaasthecellages.TheessentialdifferencebetweenPEMandalkalinewaterelectrolyzersisthelackofliquidelectrolyte,whichenablesthemorecompactsystemdesignforPEMelectrolyzers.ThecompactdesignandstructureallowsPEMelectrolyzerstooperate at differential pressures, where the cathode compartment pressure can be maintained at notably higherpressures,e.g.byafactorof25.Directproductionofhigh-pressurehydrogenistempting,sincethevolumetricenergydensityofhydrogengasislowandthemainsynthetizationroutesforhydrogenandcarbon(di)oxide,suchaschemicalmethanationortheFischer-Tropschprocess,requireelevatedpressures.However,thedifferentialpressureoperationfurtherinducestheadversehydrogengascrossoverandsetsalimitationontheminimumsafeloadfortheelectrolyzer.

Industrialwaterelectrolyzers,acategorydominatedbytheconventionalalkalinetechnology,arecharacterizedbyhighDCcurrents.Therefore,therectifiersinconventionalindustrialwaterelectrolyzersaretypicallybasedonthyristorsanddiodes,whichswitchaccordingtothelinefrequency.Useofmoremodernpowerelectronicconverterscoulddecreasetheharmoniccontentandtheresultantheatlossesintroducedbylinefrequencyswitching.However,semiconductorsusingforcedcommutationwouldrequiremodularconversionstructurestomoderatethesuppliedcurrenttosuitablelevels.Theeffectofcurrentandvoltageharmonicsonthespecificenergyconsumptionofwaterelectrolysisprocesses—aquantity,whereFaradayefficiencyshouldbeincluded—isyettobethoroughlystudied.Linefrequencyswitchinginthepowersupplyalsoexposestheelectrolyzerstacktocontinuoushighlydynamicoperation.

A Power-to-Hydrogen laboratory setup is built in a shipping container to study both the alkaline and PEM waterelectrolysisprocesses.Theelectrolyzersemployedarea2.8kWBabyPIELalkalineelectrolyzermanufacturedbyMcPhy

anda4.5kWPEMelectrolyzerbyEWII.ThestudiedPEMelectrolyzeroperatesatanodeand cathode compartment pressures of150–250 kPa and 1500–5000 kPa,respectively. The hydrogen laboratorysetupisalsovirtuallyconnectedtoa206.5kWpsolarPVpowerplanttostudycontroloptimization strategies from bothelectricity production and stackperformancepointofview.Measurementsare stored using a Windows PC runningLabVIEW.


145

AbstractNo.208

Theeffectoflinefrequencyandforcedcommutationonthelossesoftheelectrolyzerstackandthepowersupplyunit

VesaRuuskanena,JoonasKoponena,AnttiKosonena,MarkkuNiemeläaandJeroAholaaaLUTSchoolofEnergySystems,LappeenrantaUniversityofTechnology,Finland

[email protected]

Summary.Tostudytheeffectofpowerqualityontheelectrolyzerstackperformance,aprogrammableDC+ACpowersupplyunitusingacommerciallyavailablefrequencyconverterhardwareisimplemented.Apower-hardware-in-loop(PHIL)simulatorwithnominalcurrentof405Aisbuilttotestindustrial-scaleelectrolyzersupplypowerelectronicsunderrealisticloadconditions.

Abstract.OwingtotherequirementforhighDCcurrents,therectifiersinconventionalindustrialwaterelectrolyzersare typically based on thyristors and diodes. However, switching according to the line frequency generates highamplitudeharmonicstothesuppliedcurrentandvoltage.Theharmonicsgenerateadditionalheatlossesinthewaterelectrolysisprocess,andcancauseprematureagingoftheelectrolyzerstack.Usingpassivefilters,especiallyontheMWscale,canbeunfavorablebecauseofthehighamplitudeandlow-frequencyharmonicsintroducedbytherectification.Applicationofmoremodernpowerelectronic convertersmaybebeneficial,butwould requiremodular conversionstructurestosharethesuppliedcurrentstosuitablelevelsforsemiconductorsusingforcedcommutation.

Atransistor-basedpowersupplyforwaterelectrolyzersystemisdevelopedtoaddthedesiredACfrequencycontenttotheelectrolyzer stack supplyvoltage.Thepowersupply isbasedonacommerciallyavailable industrial three-phasefrequencyconverter.Theinverterisequippedwithamodifiedcontrollerboardallowingcustompulse-widthmodulator(PWM)implementationandhighbandwidthvoltage/currentreferencetrackingthroughEtherCATfieldbus interface.TheloadisconnectedbetweentwoinverterphaselegsforminganH-bridgetoallowthreevoltagelevels(0,+UDC,and-UDC).Thecurrentsof inverter legsareusedasafeedbacksignalforacurrentcontrollersettingtheDCcurrenttoadesiredvalue.Atthesametime,voltageharmonicsareaddeddirectlytothecontrolleroutputvoltagereferencesignal.

Thevoltagewaveforms,emulatingpureDCsupplyandlinefrequencyswitchingpowerelectronicswithhighharmoniccontentaregeneratedtostudytheeffectofthefrequencycontentofDCpowerontheperformanceoftheelectrolyzerstack.ThestackefficiencyoftheBabyMcPhyalkalineelectrolyzer,withhydrogenproductioncapabilityof0.4Nm3andthemaximumelectricalpowerconsumptionof2.8kW,ismeasured.ThetypicalDCcurrentandvoltagevaluesoftheelectrolyzerare35Aand65V.

A PHIL simulator is implemented using commercially available water cooled converters to fast and safely testelectrolyzerpowersupplyelectronics.ThePHILsimulationenablestestingofindustrialscalepowerelectronicsunderrealistic loadconditionsemulatingthedifferentelectrolyzerstackswithouthardwarechanges.ThePHILsimulator iscapableofhandlingcontinuouscurrentupto405Aandmorethan600Vofvoltage,producingapowerof250kW.ThePHILsimulatorismodularandcanbedividedintothreeoperationalparts.

The power supply module is the actualdevice under test (DuT) supplying DCcurrenttotheelectrolyzer.Theelectrolyzeremulator acts as a variable impedance tocontrol the emulator interface currentbased on the measured electrolyzerinterfacevoltage.Theemulatorhasaboostconverter and an LCL filter between theboostconverterandthepowersupplyunit.The grid interface returns the electricenergysafelybacktothegrid.


146

AbstractNo.209

HydrogenproductionasapartofP-to-Xsystem

AnttiKosonena,JoonasKoponena,VesaRuuskanena,JeroAholaa,CyrilBajamundib,PekkaSimellb,FranciscoVidalb,ChristianFrilundb

aLUTSchoolofEnergySystems,LappeenrantaUniversityofTechnology,FinlandbVTTTechnicalResearchCentreofFinland

[email protected]

Summary.PEMelectrolyseristestedinaP-to-Xsystem,whereelectricityisproducedfromsolarPV,CO2capturedfromair,andthehydrogenandCO2aresuppliedtoaFischer-Tropsch(FT)reactor.Thepilotsystemsetlimitationsforthedynamics,pressurelevels,productionrate,andstorageusedinhydrogenproductionofaPEMelectrolyser.

Abstract.EUhas set targets for2050 to cut carbonemissions to80%below1990 levels in theEU. Toachieve thisstringent target, thewhole energy system shall be restructured so that it ismore based on renewable electricity.Dependingonthelocalconditionsrenewableenergyproductionbasedonsolarandwindpowermaybecomeoneofthekeytechnologiesenablingthischange.Inthiscase,weneedanefficientmeansofenergystorageaswellasabridgebetweenelectricityandthetransportation fuelsector.This linkcanberealizedthroughahydrocarbonactingasanenergystorage.Inthefuture,thecarbonisrecycledanditcanbecapturedbacktofuels.“Re-carbonized”energysystemin2050isillustratedinFig.1.

Power-to-X concept arise as a synergic solution forstoring the energy from intermittent renewableenergy sources suchaswindandsolar,and forCO2mitigation. Theelectrical energyproducedby theseenergy sources is converted to hydrogen throughelectrolysisofwater,whichcanbefurtherconvertedto carbon based chemicals. Electric power can beconverted to several products collectively called asPower-to-X, in which “X” can refer to gas or liquiddepending on the applications. The combination ofrenewable electrical and heat power and capturedCO2as inputsforthePtXcould leadtoapotentiallycarbon neutral fuel cycle, and truly sustainablesyntheticfuels.

Thepilotdemonstrationsystemtobebuiltconsistsoffour sea containers and a solar power plant. Eachcontainer includes individual sub-systems. Thecontainers include hydrogen production based onPEM water electrolyser technology, a direct aircapture(DAC)system,synthesis,andbufferstoragesystems. These are connected together to form anenergy conversion system that can be utilized forexampleasanSNGfillingstation.

The hydrogen container includes a 4.5 kW PEMelectrolyser(33cellstacks)withadditionaldevices(apowersupply,waterpurification,ahydrogendryer,two 350 l composite bottles for hydrogen storage)thatarenecessaryfromtheoperationpointofview.TheschematicofthecontainerisillustratedinFig.2.

Fig.1.“Re-carbonized”energysystem.

Fig.2.PEMelectrolysercontainer.


147

AbstractNo.210

DetectionandmodellingofhydrogencrossoverinPEMelectrolysersusingEIS

JulioCésarGarcía-Navarroa,SangramAshokSavanta,IndroShubirBiswasa,MathiasSchulzea,K.AndreasFriedricha,baGermanAerospaceCenter,InstituteofEngineeringThermodynamics,Pfaffenwaldring38-40,70569Stuttgart,

GermanybUniversityofStuttgart,InstituteofEnergyStorage,Pfaffenwaldring31,70569Stuttgart,Germany

[email protected]

Summary.WeinvestigatehydrogencrossoverinaPEMelectrolyserwithvaryingpressuredifference.EISshowspseudo-inductivebehaviourinthelowfrequencyrange.Weusesurfacerelaxationimpedancetomodelthepseudo-inductiveeffect.Wefindevidenceofrelationbetweensurfacerelaxationandhydrogencrossover.

Abstract.Detectionofhydrogencrossoverinprotonexchangemembrane(PEM)electrolysers,utilizingelectrochemicalimpedancespectroscopy(EIS)hasbeenscarcelystudied,despitehavingapotentiallymeasurableeffect.Inthiswork,westudythehydrogencrossoverasa functionofpressuredifference, from0to9bar,withamembraneelectrodeassembly(MEA)madeofNafion115.TheEISwascarriedoutat1.5Acm-2and65°C.Wefindalowfrequencypseudo-inductivebehaviour,attributed toacompetitionbetweenhydrogenoxidation reaction (HOR)andoxygenevolutionreaction (OER), the former fuelled by hydrogen crossing over from the cathode to the anode. We modelled thecompetition using surface relaxation impedance, having two components: resistance and time. The probability ofcompetition increaseswithhydrogencrossover rate,detected inEIS spectraasa rise in the low frequencypseudo-inductivebehaviour,and itwasconfirmedbyaproportional relationshipbetweensurfacerelaxationresistanceandhydrogencrossoverrate.


148

AbstractNo.211

DemonstrationofImpedanceSpectroscopyasaMethodtoEvaluateLossesofPolymerElectrolyteMembraneElectrolysisCellsduringWaterElectrolysis

KatrineElsøea,LailaG.-Madsenb,GüntherG.Schererc,JohanHjelma,MogensB.MogensenaaTechnicalUniversityofDenmark,Frederiksborgvej399,4000Roskilde,DenmarkbEWIIFuelCellsA/S,EmilNeckelmannsVej15A&B,5220OdenseSØ,Denmark

cTUMCREATE,[email protected]

Summary.

Electrochemicalimpedancespectroscopy(EIS)isinthistalkdemonstratedasatooltoinvestigateprocessescontributingtolimitationsinthepolymerelectrolytemembraneelectrolysiscell(PEMEC)performanceduringelectrolysisofwateratambientpressureandat61˚C. Ahypothesisdescribingtheprocesses limitingthecellperformance issuggestedbasedontheEISmeasurements,cyclicvoltammetryandiV-characteristics.

Abstract.

Incombinationwithothertechniquessuchasscanningelectronmicroscopy,cyclicvoltammetryorXPS,justtomentionafewexamples,electrochemicalimpedancespectroscopyisavaluableelectrochemicalmethodusedtocharacterizeprocessescontributingtoimpedancelossesinelectrochemicalcells.

Thetechnologyhassuccessfullybeendemonstratedonsolidoxidecells,butliteratureresolvingimpedancespectraofPEMECs is sparse. This presentation demonstrates the experimental approach ADIS (Analysis of Differences inImpedanceSpectra)(Jensenetal.,2007)knownfromsolidoxidecellresearchtoresolvetheimpedanceofoperatingPEMECs.TheEISresults,someofwhichareshowninfigure1,revealtwodependentprocesseswithsummitfrequenciesofapproximately0.4and100HzsignificantlycontributingtotheoverallperformancelossoftheoperatingPEMEC.CyclicvoltammetryandiV-characteristicsmeasuredonthecellsareaccompanyingtheEISmeasurementsandahypothesistryingtoexplaintheobservedelectrochemicalresultsofthethreemethodsisgiven.

Reference.

S. H. Jensen et al. (2007). AMethod to Separate Process Contributions in Impedance Spectra by Variation of TestConditions.JournalofTheElectrochemicalSociety,154(12),B1325-B1330.

Figure16.ElectrochemicalimpedancedataobtainedonaPEMECoperatingatambientpressure,61˚Cand1A/cm2representedinaNyquistplot(uppergraph)andinaBodeplot(lowergraphs).


149

AbstractNo.212

EngineeringofhightemperaturePEMWE

HuaLia,AkikoInadaa,KenjiTerabarua,HironoriNakajimaa,andKoheiItoaaDepartmentofhydrogenenergysystem,KyushuUniversity

[email protected]

Summary.

HightemperaturePEMWEisoptimized,inengineeringmanner,intermofoperationcondition,currentcollector,andflowfieldpattern.Electrochemicalcharacterizationrevealsthattheseengineeringparameterimpactonoverpotentialthroughwaterbehaviourincell,andanoptimizedpairoftheparametercanreach1.69@2A/cm2,120°C,0.3MPa.

Abstract.

High temperature operation is a possible solution to reduce the cost of PEMWE. Increasing temperature generallyresultsinadecreaseofactivationoverpotentials,especiallyinoxygenevolutionreactionprocess.Lessoverpotentialintroducedby raising temperature enables tooperatePEMWEunder ahigh currentdensity conditionwith smalleramount of catalyst, resulting in less cost. However, as a trade-off, the high temperature operation tends to causedehydration of polymer electrolyte membrane (PEM), and raises ionic resistance (ohmic resistance), resulting indecreasingtheperformanceofPEMWE.

This study elucidates overpotential in PEMWE under high temperature conditionwith changing operationparameters and embedded components, and challenges to reduce electrolysis voltage. In addition to the ohmicoverpotentialdirectlycausedbythePEMdehydration,theotheroverpotential,suchasactivationandconcentrationoverpotential, is carefullyaddressedwithelectrochemical characterization.Changingoperationparameters, suchaspressureandflowrateofsuppliedwater,haseffectonthewaterbehaviourandoverpotential,andadequatechoiceofparameters to suppress the overpotential is explored. Also, different structures of current collector and flow fieldpattern,which is expected to change thewater behaviour, are embedded into a PEMWE cell, and try tominimizeelectrolysisvoltageandtomaximizeelectrolysisperformance.

Ontheeffectofoperationparametersonelectrolysisperformance,electrochemicalcharacterizationrevealsthat simply elevating temperature causes a significant increase of concentration overpotential and a rather smallincreaseofohmicoverpotential.Inadditiontoincreasingwaterflowrateasusuallytreated,raisingoperatingpressureisfoundtosuppresstheconcentrationoverpotential.Thisfindingsuggeststhatcoexistenceofvapourandliquidphasesincellbyincreasingoperatingpressureiskeywhenoperationtemperatureiselevated.

The structure of anode current collectors (ACC) are optimized to minimize overpotentials. Hydrophilicity(contactangle)andthicknessoftheACCimpacttheelectrolysisvoltagethroughconcentrationandohmicovervoltages.SmallercontactangleandthinnerACCintherangeof0-120°and200-300μm,respectively,enhancewatersupplytoanodecatalystlayeranddecreasestheconcentrationandohmicoverpotentials.Inaddition,anoptimizedporediameterinACCissuggestedtobe21μm,whichcanminimizetheelectrolysisvoltage.

Flow field pattern and flow configuration are also examined under high temperature condition. Amongcascade,parallel, and serpentinepattern, the cascadepatternminimizes the concentrationoverpotential. The flowconfiguration(counterandparallelflow)haslittleimpactontheelectrolysisperformance.DifferentfromPEMfuelcell,watersupplyperformedinPEMFCdistributeswaterinhomogeneousmanner,andthisnaturetrivializetheeffectofflowconfiguration.


150

AbstractNo.213

TheHyBalanceProjectwilldemonstratehowhydrogencanbeusedasmeantostoreenergywhichinturnwillbeusedforIndustryandfuel-cellvehicles

LouisSentis

AirLiquideAdvancedBusinessandTechnologiesEuropelouis.sentis@airliquide.com

Summary.HyBalanceisaprojectthatwilldemonstratetheuseofhydrogenintheenergysystems.Thehydrogenwillbeproducedfromwaterelectrolysis,enablingthestorageofcheaprenewableelectricityfromwindturbines.Itwillthushelpbalancethegridandthegreenhydrogenwillbeusedforcleantransportationandintheindustrialsector.

Abstract.Inaworldwherethereductionofcarbonemissionsisadailychallengeforeveryone,AirLiquideisworkingondeveloping innovative technologies and solutions for reducing carbon emissions during the hydrogen productionprocess.Althoughhydrogenismainlyusedtodayforindustrialpurposesinchemistryandrefinery,itisincreasinglyusedinothersectors,suchascleantransportation.

Clean Hydrogen can be produced through water electrolysis. Air Liquide is demonstrating the advantages of thistechnologybyleadingamajorproject inDenmark,HyBalance.Thisproject isatechnologyshowcaseforsustainabledevelopmentpathwaysinEurope.Forthisreason,itreceivesbothEuropeanandDanishsupport,throughtheEuropeanFuelCellsandHydrogenJointUndertakingandtheDanishForskELprograms.

HyBalancewilldemonstratethecompletevaluechain,fromenergystoragethroughtheproductionofhydrogenfromrenewablesources(windturbines)toitsdistributionforapplicationsincleantransportationandtheindustrialsector.

Thefacilitywillalsoprovideservicestothepowergrid.Energinet.dk,thegridoperator,alsocoordinatoroftheForskELprogram,managesthehighestsharesinEuropeofintermittentwindenergyinadomesticpowermix.Windpowerisfluctuating and requires adequate flexibility operations to ensure balance in the electricity grid. Dynamic waterelectrolysisofferssuchflexibilityusingelectricitywhenthepricesareloworwhenthereisaneedforbalancingbytuningthepowerconsumptioninapromptandreliablemanner.

TheHyBalanceprojectwilldevelopamodelinwhichtheoperationofthehydrogenplantistriggeredasfunctionofthepowerprices,thepowerbalancingservicepricesandthehydrogendemandforecasts.

HyBalancewilluseaProtonExchangeMembrane (PEM)electrolyser,deliveredandmaintainedbyHydrogenicsandproducingupto230Nm3ofhydrogenperhour.TheprojectwilldemonstratethehighlydynamicoperationsofthePEMtechnology to provide grid services togetherwith the requirements of an industrial environment: a high efficiencycommitmentofthecompleteprocessfrompowertopurehydrogen,lownoiseemissions,limitedpowerfactorandthereliabilityandmaintainabilityofthewholesystem.HyBalanceisdesignedfor15yearsofoperationandwillbesupplyingindustrialcustomers.Forthatpurpose,Hydrogenicshasdesignedbuiltandtestedacustomizedproduct.

HyBalancefacilitywillbecapableofsupplyingafleetofmorethan1000FuelCellElectricVehicles(FCEVs).Morethan60FCEVsarealreadyontheroadtodayandAirLiquide isoperatinganetworkof fivestations inDenmark throughCopenhagenHydrogennetwork.FCbusesprojectsarealsobeingdeveloped.ThankstoHyBalance,thesevehicleswillbeabletobefueledwithrenewablehydrogen.

ThefacilityisnowbeingbuiltinHobro,inthenorthernpartofJutlandinDenmark.ThestartoftheoperationsisplannedforOctoberthisyear.


151

AbstractNo.214

AdvancesinPEMElectrolyzerComponents

MadeleineOdgaard,MustafaHakanYildirimandLailaGrahl-MadsenEWIIFuelCellsA/S,EmilNeckelmannsVej15,DK5220OdenseSØ,Denmark


Summary.Thestep fromsmall-scaleprototypemanufacturing to realproducts isamajorchallenge in theeffortofmakingPEMelectrolysersacommercialsuccess.Thestatusofnovelcomponentsandthechallengesrelatedtotheirmaterialsandprocessingbyadesignapproachisaddressedinthepresentation.

Abstract.Duetotheincreasingenergydemandoftheworld,theneedforcleanandrenewableenergysourcesisrising.Hydrogencomingfromwaterelectrolysisusingrenewableenergysourceslikewind,sunandwavesisoneofthecleanestalternativestofossilfuels.Polymerelectrolytemembraneelectrolysercell(PEMEC)technologymakesthisoptionpossible.However,thereareseveralmajormarketchallengesforPEMECinthecompetitionwithothertechnologies.Oneofthemistheproductscalerequiredbygridowners.Multi-MWelectrolysersystemsareneededtobalancethegrid.Inordertoactualisethat,theelectrochemicallyactivearea,theoperatingcurrentdensityandthepressurehavetobeincreased.Thiswillleadtosignificantlyhigherhydrogencrossoverandtoanewdemandforsuppliersofmembrane–electrodeassemblies(MEAs)tochangetheircurrentproductionmethodtocopewiththerequiredincreaseintheactivearea.Multi-MWsystemswithafewlargeMWstacksarealreadyavailablefromseveralsuppliers.ThepresentMWstacksaredesignedwithlargecellareasupto1m2.Inthispresentation,thechallengesofscalingupthecatalyst-layermanufacturewhilemaintainingahigh-performingMEAarediscussed.Thetacklingofthevariouschallengesthroughthedevelopmentofnewtechnologyandadvancedproductsistreated.Thus,lightissheduponthemanufactureoflarge-scaleMEAswithareasonthe1-m2scalewithafocusoncomponentsintegrityaswellasoncompliancewiththeOEMrequirementsforfurtherimprovementofperformance,durabilityandcost.


152

AbstractNo.215

DeterminationofthebipolarplateagingunderPEMelectrolysisoperation

ManuelLangemanna,MartinMüllera,WernerLehnertbandDetlefStoltencaForschungszentrumJülichGmbH,InstituteofEnergyandClimateResearch,IEK-3:ElectrochemicalProcess

Engineering,D-52425Jülich,GermanybModelinginElectrochemicalProcessEngineering,RWTHAachenUniversity,Germany

cChairforFuelCells,RWTHAachenUniversity,Germanye-mailofcorrespondingauthor:[email protected]

Summary.

Investigation of various bipolar plate materials via electrochemical (in situ) and contact resistance (ex situ)measurementsaswellastheconcentrationanalysisoftheprocesswaterindicatethelevelofcorrosiondevelopment.Bytheusageofstainlesssteelasbipolarplatematerialandathingoldcoatingthecorrosiondevelopmentisreducible.

Abstract.

TheintentiontoreduceGermany'sCO2emissionsoverthelongtermwillbefosternedbytheexpansionofrenewableenergysources,suchaswindpower.Sincethenetworkcoverageofsuchsystemsisstronglydependentonweatherconditionsandwillthereforeentailfluctuationintheirenergysupply,itwillbenecessarytointegratesuitablestoragesystemssothatpotentialbottlenecksintheelectricitysupplymaybebridged.Onestorageoptionisthegenerationofhydrogen,whichcanbeconductedbymeansofusingrenewablepowertodrivewaterelectrolysis.Duetoitsdynamicoperationmode, thepolymer electrolytemembrane (PEM) electrolysis is particularly suitable, because it can reactrapidlytovaryinginputcapacities.Oneimportantcellcomponentisthemetallicbipolarplate(BPP),whichisresponsiblefortheelectricalconnectivityalongthestackandthedistributionoftheliquidandgaseousmediainsidethecell.Thestate-of-the-artbipolarplatematerialisTitanium[1].

In the context of our workwe investigate commercially available and in the industrywell-known corrosion stablematerialstobeusedduetotheirsuitabilityasbipolarplatematerialinPEMwaterelectrolysis.Theaimistoidentifyalloys thatarestable in the long term,ormaterial combinations thatarecharacterizedby lowcorrosionwithgoodelectrical contactproperties.Anevaluationof the corrosion thatdevelops is carriedoutbyusing theexperimentalinvestigationsinoutsourcingcorrosionandsinglecellteststhroughanalysisofthemetalionemission,aswellastheincreaseincontactresistancethatresultsfromthestrain,influencedbythecellpotential,temperatureandpHvalueoftheoperatingwater[2].

Usingboth,analyticalelectricandelectrochemicalmethods,theselectionofpossiblesubstrateandcoatingmaterialscouldbelimitedtoafewmetalswithinthePSE.InapreselectionvariousalloyswerecharacterizeundersimulatedPEMelectrolysisconditionstofindoutmorestablematerials.Subsequentcontinuousandlong-termtestsunderrealPEMelectrolysisconditionshaveshownthatacombinationofstainlesssteelsubstrateandathingoldlayeralreadyresultsinsignificantlylowermetalionemissionsandvirtuallynoincreaseincontactresistancecomparedtothebenchmark.

[1] M.Carmo,D.L.Fritz,J.Mergel,D.Stolten,AcomprehensivereviewonPEMwaterelectrolysis,InternationalJournalofHydrogenEnergy,38(2013)4901-4934.

[2] M.Langemann,D.L.Fritz,M.Müller,D.Stolten,ValidationandcharacterizationofsuitablematerialsforbipolarplatesinPEMwaterelectrolysis,InternationalJournalofHydrogenEnergy,40(2015)11385-11391.


153

AbstractNo.216

H2FUTURE,Hydrogenfromelectrolysisforlowcarbonsteelmaking

MarcelWeedaa,RudolfZaunerb,ThomasBuerglerc,KlausSchefferd,RonaldEngelmaire,IrmelaKoflerf,aECN,Radarweg60,1043NT,Amsterdam,TheNetherlands

bVERBUNDSolutionsGmbH,Europaplatz2,1150Vienna,AustriacvoestalpineStahlGmbH,voestalpine-Straße3,4020Linz,Austria

dSiemensAG,Günther-Scharowsky-Straße1,91058Erlangen,GermanyeAustrianPowerGridAG,WagramerStraße19,IZD-Tower,1220Vienna,Austria

fK1-METGmbH,Stahlstraße14,4020Linz,Austriae-mailofcorrespondingauthor:[email protected]

Summary.ThiscontributionwillintroduceandexplaintheH2FUTUREproject.Theprojectwilloperatea6MWstate-of-the-artPEMelectrolyserwithinanintegratedsteelworkstodelivergreenhydrogenforlowcarbonsteelmaking.Inaddition,theunitwillservewithinapoolofdemand-responseunitstoprovideservicesforgridbalancing.Abstract.Novelelectrolysersarethetechnologicalcornerstonethatwillmakehydrogensufficientlyaffordableinthefuture to act as an energy carrier in a low-carbon energy system, and to enable decarbonisation of several mainindustrialprocesses,suchassteelmakingandfertilizerproduction.TheH2FUTURE1projectaimstomakeasignificantcontributiontothisdevelopment.Ina4.5-year,€18millionfielddemonstrationproject,aconsortium,ledbyAustrian-basedelectricitycompanyVERBUND,will constructandtestoneof theworld’s largestprotonexchangemembrane(PEM)electrolysisplantsforproducinggreenhydrogen.

A 6MW state-of-the-art Siemens electrolyserwill be built and operated on thepremises of voestalpine in Linz, Austria, and the hydrogen produced will beintegratedintoregularoperationsatthesteelworks.Assuch,theprojectisanewstepinthedevelopmentofarouteforsteelmakingusingpurehydrogen,whereironoreisdirectlyreducedbyhydrogeninashaftfurnace.Theresultingdirectreducediron(DRI,alsocalledspongeiron)isfurthertreatedinanelectricarcfurnace(EAF)to produce steel. By producing hydrogen from water electrolysis and usingrenewableelectricityforbothelectrolysisandtheEAF,thisprocessschemeoffersapromisingroutetolow-carbonorevencarbon-freesteelmaking.

As part of the project, VERBUNDwill also implement the unit within a pool ofdemand-responseunits to test its capabilities toprovidegridbalancing services,suchasprimary,secondaryortertiaryreservepower.Deploymentwilltakeplacebased on commercial contracts with the Austrian transmission system operatorAPG,whichisalsoapartnerintheproject.

The capital cost reduction of electrolysers is one of themajor challengeswhenputting large-scale installations into economic operation. The target of thedemonstrationistoreach€1000/kWfortheelectrolysersystematnominalpower,includingpowersupply.Theachievementofthisandothertechnical,economicand

environmental performance targets will be analysed and assessed by knowledge institutes ECN and K1-MET inconjunction with the other partners. This will be done based on data resulting from an extensive pilot plant testprogrammeandan18monthquasi-commercialoperationalperiodthatareforeseenwithintheproject.Theresultswillbeusedforthedevelopmentofabusinessplantocontinueoperationoftheunitaftertheprojectperiod.Inaddition,theresultswillformthebasisofrolloutscenarioswhichdescribethetechnicalandeconomicconditionsunderwhichelectrolysisbecomesaviablesolutionforthesteelindustry.Thiswillinvolveaneconomicandenvironmentalimpactassessment for the case that EU28-wide implementation of the demonstrated solution takes place, including anassessmentoftheimpactontheelectricitysystem.1ThisprojecthasreceivedfundingfromtheFuelCellsandHydrogen2JointUndertakingundergrantagreementNo735503.ThisJointUndertakingreceivessupportfromtheEuropeanUnion’sHorizon2020researchandinnovationprogrammeandHydrogenEuropeandN.ERGHY.

Figure17Steelplantbasedondirectreducedironproductionwithpurehydrogenfromelectrolysis.


154

AbstractNo.217

Ironsulfidesaslow-costbioinspiredcathodecatalystsforprotonexchangemembraneelectrolyzers

C.DiGiovanni,1,2A.Reyes-Carmona,3J.Rozière,3D.Jones,3B.Lassalle-Kaiser,4J.Peron1,C.Tard2,M.Giraud*11LaboratoireITODYS,UMR7086CNRS,France;2Laboratoired’ElectrochimieMoléculaire,UMR7591,France

3InstitutCharlesGerhardt,UMR5253,France4SynchrotronSOLEIL,Francee-mail:[email protected]

Summary.Wepresentthesynthesesandcharacterisationsofdifferentironsulfidesandtheirperformancesascathodecatalystsinprotonexchangemembraneelectrolysers.WefoundafairlygoodactivityforpyriteFeS2,showinga400mVoverpotentialat2Acm-2comparedtostandardPt/Candhighstabilityover100h.

Abstract.Severalelectrocatalystsbasedonnon-noblemetalsulfides,phosphatesorphosphideshaverecentlybeenreportedfortheirhighactivitytowardhydrogenevolutionreaction(HER).[1]Giventheubiquityofironsulfidemineralsinnature,suchasPyrite,which isthemostabundantmineralonEarth’ssurface,wepropose ironsulfidesasanewmaterialsforHER.[2,3]

Figure1:IronandSulfurformaloxidationstates.

In order to investigate the influence of iron and sulfur oxidation states and crystal structure on theHER,we havesynthesizedFeSnanoparticlesofdifferentstoichiometry:pyrrhotiteFe9S10,greigiteFe3S4andpyriteFeS2(figure1)usingasoftchemistryroute,thepolyolmethod.ThenanoparticlescrystallinestructureandmorphologywerecharacterizedbyXRDandSEMandTEM.Mössbauerspectroscopywasusedtoprobetheironoxidationandmagneticstatesineachmaterial. Composite catalyst layers made of FeS nanoparticles, carbon and Nafion were coated on glassy carbonelectrodestomeasureelectrochemicalperformances.Thematerialsshowoverpotentialsbetween200and300mV,theirdurabilityandrobustnesswasassessedbycontrolled-potentialelectrolysis.Quantitative(≥0.99)FaradicyieldforhydrogenevolutionwasconfirmedbyGCandvolumetricmeasurements.EXAFSandXANESspectrawererecordedonthe composite films in-operando in an electrochemical cell at the Fe and S K-edges to follow the evolution of thematerialsstructureduringtheHER.TheFeSnanoparticleswerealsotestedascathodecatalystsinanelectrolyzer.Pyritewasfoundtobethemostactivecomparedwithgreigiteandpyrrhotite,andshoweda400mVoverpotentialat2Acm-

2comparedtostandardPt/Candhighstabilityover100h.

[1]C.Morales-Guio,L.-A.Stern,X.Hu,Chem.Soc.Rev.2014,43,6555

[2]C.DiGiovanni,W.A.Wangetal.ACSCatal.2014,4,681

[3]C.DiGiovanni,J.Peronetal.ACSCatal.2016,6,2626


155

AbstractNo.218

TungstenCarbideSupportMaterialsfortheHydrogenEvolutionReactionProducedbytheSelf-PropagatingHigh-TemperatureSynthesisMethod

MortenG.PoulsenaandShuangMaAndersenaaDepartmentofChemicalEng.,BiotechnologyandEnvironmentalTech.,TechnicalFaculty,

[email protected]

Summary.We present the synthesis of tungsten carbide and other relevant ceramicmaterials for use as catalystsupports inelectrolysersforthehydrogenevolutionreaction,usingtheself-propagatinghigh-temperaturesynthesismethodwhichallowsforrapidandupscalablesynthesis.

Abstract.Tungstencarbide(WC)showspromiseasanalternativeplatinumsupportmaterialinPEMelectrolysers,duetoitsco-catalyticabilitytowardsthehydrogenevolutionreaction(HER)anditsimprovedstabilityincomparisontomoretraditional carbonmaterials [1,2]. The development of high-surface areaWCmaterials could lead to reduction inplatinumloadingandincreasedlifetimeofelectrolysercathodes[3].

FormationofWCthroughtheuseofself-propagatinghigh-temperaturesynthesis(SHS)ispossiblebyreactingamixturecontaininga tungstenprecursorwitha reductant in thepresenceof carbon.Once ignited, theexothermic reactionresultsintheformationofpuretungsten.Tofacilitatetheconversionoftungstentotungstencarbide,thereactioniscarriedoutinapressurisedreactor.

OurresearchisfocusedondevelopingtheSHSmethodtowardstheformationofWCandWC-basedmaterialswiththepropertiesdesiredforcatalystsupports inPEMelectrodes.This includestestingofvariousprecursors,carbontypes,andcompositionsofthereactantmixturewhileobservingtheeffectsonparticlesize,morphologyoftheproduct,andelectrochemicalactivity.

Withthispresentation,wehopetoilluminatethepotentialoftheSHSmethod,whichallowsfortherapidandupscalablesynthesis of a plethora of ceramic materials that show potential for use in electrochemical energy conversiontechnology.Atthesametime,wehopetopresentourownworkonthesynthesisofWCandsimilarmaterialsbythismethod.

[1] D.V.Esposito,S.T.Hunt,A.L.Stottlemyer,K.D.Dobson,B.E.McCandless,R.W.Birkmire,etal.,Low-costhydrogen-evolutioncatalystsbasedonmonolayerplatinumontungstenmonocarbidesubstrates,Angew.Chemie-Int.Ed.49(2010)9859–9862.doi:10.1002/anie.201004718.

[2] H.Zhuang,A.J.Tkalych,E.A.Carter,UnderstandingandTuningtheHydrogenEvolutionReactiononPt-CoveredTungstenCarbideCathodes,J.Electrochem.Soc.163(2016)F629–F636.doi:10.1149/2.0481607jes.

[3] M.Carmo,D.L.Fritz,J.Mergel,D.Stolten,AcomprehensivereviewonPEMwaterelectrolysis,Int.J.HydrogenEnergy.38(2013)4901–4934.doi:10.1016/j.ijhydene.2013.01.151.


156

AbstractNo.219

CurrentdensityimpactonhydrogenpermeationduringPEMwaterelectrolysis

PatrickTrinkea,BorisBensmanna,*andRichardHanke-RauschenbachaaLeibnizUniversitätHannover

*[email protected]

Summary. This contribution presents experimental data that emphasizes the strong effect of current density onhydrogenpermeation.Forexample,acurrentdensityof0.55A/cm2cancausessimilarpermeationratesasahydrogenpressureof10bar.Thesecondpartofthiscontributionshowsatheoreticalexplanationofthiseffect.

Abstract.HydrogenpermeationisanimportantphenomenaforPEMwaterelectrolyzers,duetothethreemainreasonssafety issues, degradation and efficiency losses. The present contribution shows hydrogen volume fractionmeasurementswithin theanodeproductgasduringPEMwaterelectrolysis fordifferent temperaturesandcathodepressures.Especially,athighcathodepressuresthehydrogenvolumefractionsareclosetothelowerexplosionlimitofhydrogeninoxygen(≈4vol.%)(Fig.1(a)).Consequently,thissafetyissuelimitstherangeofoperationconditions.

Withtheexperimentalhydrogenvolumefractiondata(Fig.1(a))itisdifficulttopredicatethecourseofthehydrogenpermeation ratewith increasing current density. Therefore, the experimental date is converted into the hydrogenpermeationrate(Fig.1(b)).

Fig.1:CathodepressureeffectatT=60°Con:(a)hydrogenvolumefractionand(b)hydrogenpermeationrateversusthecurrentdensity.

InFig.1(b) itcanbeseenthathydrogenpermeation increases linearwith increasingcurrentdensity.The impactofcurrentdensityonthehydrogenpermeationisverystrongincomparisone.g.acurrentdensityincreaseof0.55A/cm2cancauseapermeationincreaselikeacathodepressureincreaseof10bar.

Thisstrongandsurprisingeffect is theoreticallydiscussed in thesecondpartof thiscontribution.Differentpossibleexplanations, such as temperature and pressure increaseswith increasing current density are evaluated. Themostprobableexplanation is thatdue tomass transfer limitations a supersaturationof dissolvedgaswithin the catalystionomerfilmarisesthatcausesthisstronginvestigatedincreaseinpermeation.

Acknowledgements.TheauthorsgratefullyacknowledgethefinancialsupportbytheFederalMinistryofEducationandResearchofGermany(BMBF)intheframeworkofPowerMEE(projectnumber03SF0536B).


157

AbstractNo.220

HighlyActiveIridiumNanoparticlesforAnodesofProtonExchangeMembrane(PEM)Electrolyzers

PhilippLettenmeiera,SchwanS.Hosseinya,V.A.Savelevab,SpirosZafeiratosb,E.R.Savinovab,AldoS.GagoaandK.AndreasFriedricha

aInstituteofEngineeringThermodynamics,GermanAerospaceCenter,Pfaffenwaldring38-40,70569Stuttgart,Germany

bInstitutdeChimieetProcédéspourl'Energie,l'EnvironnementetlaSanté,UMR7515duCNRS-UniversitédeStrasbourg,25RueBecquerel,67087Strasbourg,France

[email protected]

Summary.

Addressingthe largescale introductionofPEMElectrolyzer inaCO2neutralenergychain,thereductionofpreciousmetalcontent isoneofthemainchallenges.Duetothefact, that iridiumistherarestmetal intheearthcrust, theenhancementoftheactivity,accompaniedbythereductionofelectrocatalyticmaterialforOERisabottleneck.

Abstract.

Protonexchangemembrane(PEM)waterelectrolysisisoneofthemostpromisingtechnologiesforasustainableandemission-freehydrogenproductionduetoitshighpowerdensityandhighefficiency.However,thecurrentpreciousmetalcontentforMEAs(between2and4mgcm-2)isadrawbackwhichmightbecomecriticalincaseoflargemarketintroduction in theGWrange.Therefore the reductionof iridium, the rarestmetal in theearthcrust,asanoxygenevolutionreactioncatalystisgoingtobeabottleneck.

Protonexchangemembrane(PEM)waterelectrolysisisoneofthemostpromisingtechnologiesforasustainableandemission-freehydrogenproductionduetoitshighpowerdensityandhighefficiency.1Highamountsofexpensivenoblemetals, such as platinumand iridium for cathode and anode side respectively, contribute significantly to the highinvestmentcostofthestack.Therefore,lowerloadingsofplatinumgroupmetalscanreducesignificantlytheoverallcostofPEMelectrolysis.Inthisworkwesynthesisenano-sizediridiumparticlesbyreducingIrCl3inanhydrousC2H6Oatroom temperature.2 Transmission electron microscopy (TEM) images show Ir clusters with a uniform particle sizedistribution(Figure1a).X-raydiffraction(XRD)analysisrevealsacubicfacecentredstructureoftheIrnanoparticleswithacrystallitesizeofapprox.1.8nm–2nm.XPSconfirmsthemetallicpropertiesoftheIrparticlescoveredwithaverythinoxidelayer.Thesynthesizedcatalystshowsanine-foldhigheractivitytowardsoxygenevolutionreaction(OER)than Irblackat1.51Vand25°C (Figure1b).Theeffectof thermal treatment,synthesisqualityandelectrochemicalperformanceofthecatalystsinthePEMelectrolyserarediscussedaswell.

Figure1:a)TEMimagewithparticlesizedistributionofIrnanoparticlesand,b)massactivitycharacteristicsforOERmeasuredat5mVs-1in0.5MH2SO4.Therotationspeedoftheelectrodeis2500rpmandthetemperature25°C.

References.

1. Carmo,M.,Fritz,D.L.,Mergel,J.&Stolten,D.AcomprehensivereviewonPEMwaterelectrolysis.Int.J.HydrogenEnergy38,4901–4934(2013).

2. Lettenmeier,P.etal.NanosizedIrOx-IrCatalystwithRelevantActivityforAnodesofProtonExchangeMembraneElectrolysisProducedbyaCost-EffectiveProcedure.Angew.Chemie128,752–756(2016).


158

AbstractNo.221

DegradationmechanismsofPEMelectrolyzerMEAsoperatingathighcurrentdensities

PhilippLettenmeiera,AldoS.GagoaandK.AndreasFriedrichaaInstituteofEngineeringThermodynamics,GermanAerospaceCenter,Pfaffenwaldring38-40,70569Stuttgart,

[email protected]

Summary.

Accelerating stress tests (ASTs) enable the analysis of degradation in adequate time. Here we present the agingcharacterizationofthree8cellshortstacksof120cm²activesurfacearea,runningdifferentASTprotocols.Byin-andex-situanalysiswestudytheeffectsofcatalystamount,catalysttypeanddegradationathighcurrentdensities.

Abstract.

Thefluctuatingbehaviourofrenewableenergysourceshinderstheirwidespreadintegrationintoareliableelectricitygrid.Presumably,thewideoperationrangeandrapidresponseofprotonexchangemembrane(PEM)electrolyzerscanstabilizethegrid,yetthedegradationeffectsarenotfullyunderstood.Theresultspresentedhereshownodecreaseinperformanceoverseveralthousandhours,operatingconstantanddynamicallya8-cellstack(120cm²activearea)atupto4Acm-2,withcommercialmembraneelectrodeassemblies(MEA).Themaximumelectrolyzerefficiencyisachievedatconstant1.7Acm-2.Theefficiencyonlydecreaseslessthan3%whendoublingthecurrentdensity.

BasedonEISanalysis,asemiempiricalandsimplifiedmodelwascreatedtoquantifythedegradationeffectsofeachindividualimpedanceandoverpotential.Wewereabletoobserveadecreaseofohmicresistanceasthemainagingbehaviour,ifthebipolarplatesareprotectedagainstcorrosionandoxidation,properly.Thisincreasestheefficiencybyenhancedprotonconductivitythroughthemembranebutontheotherhandalsothewaterandgascrossoverwhichdecreases the dynamic properties.1 Furthermore, we observed different degradation behaviour for Ir-metal basedcatalysts and Ir-oxides, where latter stays fairly constant during the ATS but metallic Ir-catalysts diffuse into themembraneandlooseintrinsicactivityovertime.2

Figure1:AST:>2000hat2Acm-2;SEMpostmortemanalysisofMEAs;PolarisationcurvebeforeAST(T1),inbetween(T2),andafterAST(T4)andcorrespondingEISmeasurementasNyquistdiagram(inset)

References

1. Chandesris,M.etal.MembranedegradationinPEMwaterelectrolyzer:Numericalmodelingandexperimentalevidenceoftheinfluenceoftemperatureandcurrentdensity.Int.J.HydrogenEnergy40,1353–1366(2015).

2. Lettenmeier,P.etal.DurableMembraneElectrodeAssembliesforProtonExchangeMembraneElectrolyzerSystemsOperatingatHighCurrentDensities.Electrochim.Acta210,502–511(2016).


159

AbstractNo.222

Experimentalanalysisofgas-liquidflowinPEMwaterelectrolysermini-channelsusingapermeablewall

SaeedSadeghiLafmejania,AndersChristianOlesena,SørenKnudsenKæra,SaherAl-ShakhshiraDepartmentofEnergyTechnology,AalborgUniversity,Denmark

[email protected]

Summary.Inthispaper,gas-liquidflowinmini-channelsofaninter-digitatedbi-polarplateofaPEMwaterelectrolysisisanalysed.

Abstract.Converting surplus of fluctuating electricity generated from renewable energy to hydrogen for long term(more than anhour) storage is a key component for closing the loopof the renewable energy system.PEMwaterelectrolyserconvertswatertooxygenandhighpressurehydrogenusingelectricitywithafastresponseratethatsuitstodampgridfluctuations.Oneoftheissueswithintheseelectrolysersistheirhighcost.Onemeansofreducingthecostis to increase production from the existing cells by increasing the current density from 1 (A/cm2) (at the existingconventionalcells)to5(A/cm2).Athighcurrentdensities,duetohighrateofoxygengenerationandconcentratedheatgenerationinthecell,issuesrelatedtoheatandbubblemanagementcomeupwhichmustgetmanaged.Inthisstudy,anexperimentalsetupismadeofplexiglass,Titanium-felt(Ti-felt)andmicroporousceramic.Thesetupdemonstratesasimilar gas-liquid flow encounters in PEM water electrolysis channels and anode porous media. The microporousceramic plate simulates generating small bubbles simulating the real membrane electrode assembly (MEA). Themovementofbubblesupwardinthemini-channelataspecificstoichiometricnumberisanalysedanditsmultiphaseflowregimeisidentified.

Fig.1:Geometryofthetransparenttestcase. Fig.2:Gas-liquidflowinthecellmini-channels.


160

AbstractNo.223

Experimentalstudyontheinfluenceofclampingpressureonprotonexchangemembranewaterelectrolyzer(PEMWE)cell’scharacteristics

SaherAlShakhshir1a,XiaotiCui2aandSørenKnudsenKær3aaDepartmentofEnergyTechnology,AalborgUniversity,Aalborg,Denmark

[email protected]

Summary.PEMWE’sclampingpressurehastobeoptimizedtoavoidmembranedamageasitispressurizedagainstthemetallictitaniumfiltandnottoreduceelectricalconductivitybetweenthecellcomponents.Thusclampingpressureinfluenceoncellperformance,electricalconductivity,andhydrogenandwatercross-overisdemonstratedinthiswork.

Abstract.Energytransitioncanbeledbymorehydrogenproduction.Hydrogenoffersaclean,sustainable,andflexibleoptionforovercomingdifferentobstaclesthatfacethelow-carboneconomy[1].PEMWEisoneofthemostpromisingcandidatetechnologiestoproducehydrogenfromrenewableenergysources.PEMWEcellsplitswaterintohydrogenandoxygenwhenanelectriccurrentispassedthroughit.Electricalcurrentforcesthepositivelychargedionstomigratetonegativelychargedcathode,wherehydrogenisreduced.Meanwhile,oxygenisproducedattheanodesideelectrodeandescapesasagaswiththecirculatingwater.

In the recent few years, PEMWE’s R&D has inched towards; operating conditions; such as increased operatingtemperature and cathode-anode high differential pressure operation, flow field design, stack development, andnumericalmodelling[2,3].InthisworktheeffectofclampingpressureonthePEMWEcellcharacteristics’;performance,conductivity,hydrogenandwatercross-overthroughthemembraneelectrodeassembly(MEA) isstudied.A50cm2active area PEMWE cell with double serpentine flow field channels for the anode and cathode side is used.Measurementsarecarriedoutatconstantcelltemperature(70°C)andatmosphericpressure.

EarlyresultsforIVcurvepredictthatthePEMWEcellperformanceincreaseswithincreasingtheclampingpressureatfixedtemperatureandcurrentdensity.ThiscanbeelucidatedbytheEISmeasurementswhichpredictanincrementinohmic and activation resistance at lower clamping pressure values at the same temperature and current density.Furthermore,earlyresultshavenotshownanysignificantchangeintheamountofhydrogencrossing-overfromcathodetoanodeandwaterfromanodetocathode.Thismightbeattributedtothemembranepropertieswhichmightnotbechangedsignificantlywithchangingtheclampingpressure.

IVcurvesatdifferentclampingpressurescelltemperatureof70°C.

Hydrogencross-overfromcathodetoanodeatdifferentclampingpressurescelltemperatureof70°C.

Watercross-overfromanodetocathodeatdifferentclampingpressurescelltemperatureof70°C.

References:

1- How hydrogen empowers the energy transition, Hydrogen CouncilJanuary2017,www.hydrogencouncil.com.

2- Olesen,AndersChristian,etal.Anumericalstudyofthegas-liquid,two-phaseflowmaldistributionintheanodeofahighpressurePEMwaterelectrolysis cell, International Journal of Hydrogen Energy 41, no. 1(2016):52-68.

3- Carmo, Marcelo, et al. "A comprehensive review on PEM waterelectrolysis." International journal of hydrogen energy 38.12 (2013):4901-4934.


161

AbstractNo.224

FabricationofporousCo-Pfoambyelectrodepositionforanefficienthydrogenandoxygenevolutionreactions

SeKwonOh,HyoWonKim,EunAeChoandHyukSangKwon

DepartmentofMaterialsScienceandEngineering,KoreaAdvancedInstituteofScienceandTechnologyE-mail:[email protected]

[email protected].

Ahigh-performancebifunctionalCo–Pfoamcatalystwassuccessfullysynthesizedbyfacileone-stepelectrodeposition

atahighcathodiccurrentdensity.ItexhibitsexcellentHER(η@10mAcm2,0.5MH2SO4:50mV)andOERactivity(η

@10mAcm2,1MKOH:300mV).

Abstract.

Ahigh-performancebifunctionalCo–Pfoamcatalystwassuccessfullysynthesizedbyfacileone-stepelectrodeposition

atahighcathodiccurrentdensity.Thesyntheticapproachincludesfastgenerationofhydrogenbubblesaswellasfast

deposition of Co–P, which played a key role in forming a porous Co–P foam structure. The Co–P foam exhibits

remarkableelectrocatalyticactivityandstabilityinbothacidicandalkalinesolution.It’sHERactivitywasrecordedwith

anoverpotential of 50mV in0.5MH2SO4 and131mV in1MKOHat 10mA cm2,which is comparable to thatof

commercialPt/C(η@10mAcm20.5MH2SO4:33mV,η10mA,1MKOH:80mV).TheCo–Pfoam(η@10mAcm2:300

mV)exhibitsbetterOERactivitiesthanIr/C(η@10mAcm2:345mV)andRuO2(η@10mAcm2:359mV)in1MKOH

solution.Theexcellentperformanceof theCo–P foamasanHERandOERcatalyst canbeattributed to the charge

separationbetweenCoandPinCo–Pfoamaswellastheporousfoamstructureprovidingalargeelectrochemically

activesurfacearea(ECSA).TheECSAoftheCo–Pfoamwascalculatedtobe118cm2,whichwas2.4timeshigherthan

thatofaCo–Pfilm(49cm2).


162

AbstractNo.225

APEMwaterelectrolyserbasedonmetalliciridiumelectrocatalyst,Pt/CandanAquivionmembrane

S.Siracusanoa*,V.Baglioa,S.A.Grigorievb,L.Merloc,V.N.Fateevd,A.S.AricoaaCNR-InstituteofAdvancedEnergyTechnologies(ITAE)-ViaSalitaSantaLuciasopraContesse,5-98126Messina

bNationalResearchUniversity“MoscowPowerEngineeringInstitute”,Krasnokazarmennaya,14,111250Moscow,Russia

cSolvay-VialeLombardia,20-20021Bollate(MI)–ItalydNationalResearchUniversity“KurchatovInstitute”,Kurchatovsq.,1,123182Moscow,Russia

[email protected]

Summary. Advanced membrane and electro-catalysts were developed for water electrolysis. The electrochemicalactivitywasinvestigatedinasinglecellPEMelectrolyserconsistingofaPt/Ccathode,IrmetallicanodeandanAquivionmembrane.

Abstract.AnIridiumblacknanosizedanodeelectrocatalystwascoupledtoanAquivionshort-sidechainperfluoro-sulfonicacidmembrane(90µm;EW:980g/eq)foroperationinaPEMelectrolyser.IridiumblackpowderhasbeensynthesizedbychemicalreductionofH2IrCl6x6H2OusingNaBH4aschemicalreduceraccordingtoRef.[1].Theelectrocatalysthasbeenevaluatedinasinglecellpolymerelectrolytemembranewaterelectrolyser(PEMWEs)of5cm2,basedonAquivion®membraneand30%Pt/Cascathodecatalyst[2,3].

The single cell was investigated by using linear sweep voltammetry, electrochemical impedance spectroscopy andchrono-potentiometricmeasurements.TheelectrochemicalactivityofthisMEAwasanalyzedinatemperaturerangefrom 25° to 90°C. The properties of this electrocatalyst have been investigated with the help of both ex-situcharacterizationandin-situelectrochemicaldiagnostics.

Acknowledgements

TheauthorsacknowledgethefinancialsupportoftheEUthroughtheFCHJUHPEM2GASProject.‘‘WorkperformedwassupportedbytheFuelCellsandHydrogenJointUndertakinginthecontextofprojectHPEM2GAS,contractNo.700008’’

References

[1] S.A. Grigoriev, P.Millet, K.A. Dzhus, H.Middleton, T.O. Saetre, V.N. Fateev “Design and characterization of bi-functional electrocatalytic layers for application in PEMunitized regenerative fuel cells” // International Journal ofHydrogenEnergy,Vol.35,Issue10,May2010,pp.5070-5076.

[2]S.Siracusano,N.VanDijk,E.Payne-Johnson,V.Baglio,A.S.Aricò.NanosizedIrOxandIrRuOxelectrocatalystsfortheO2evolutionreactioninPEMwaterelectrolysers.AppliedCatalysisB:Environmental164(2015)488–495

[3]S.Siracusano,V.Baglio,E.Moukheiber,L.Merlo,A.S.Aricò.PerformanceofaPEMwaterelectrolysercombininganIrRu-oxideanodeelectrocatalystandashort-sidechainAquivionmembrane.InternationalJournalofHydrogenEnergy2015,40,14430-14435.


163

AbstractNo.226

ConceptualDegradationModelforaPEMWaterElectrolyzer

SteffenFrenscha,SamuelSimonArayaaandSørenKnudsenKæraaAalborgUniversity,DepartmentofEnergyTechnology,Pontoppidanstræde111,9220AalborgEast,Denmark

E-mailofcorrespondingauthor:[email protected]

Summary. This poster presents the conceptual approach of a lifetime model for a PEM water electrolyzer. Aperformancemodelisextendedwithdegradationphenomenatopredictthelifetimeoftheelectrolyzerundervariousoperationalparameters.

Abstract. The expected lifetime of a PEM electrolyzer is a crucial measure for market maturity and financialcompetitiveness.However,laboratoryworkondegradationistime-consumingandacceleratedstresstestsareyettobe defined and validated. Simulations can support lifetime evaluations. Two approaches for the development of amathematicalmodelforlifetimeprognosisareconceivable.First,amechanisticmodelbasedonphysicaldegradationmechanismsofcrucialcomponentssuchasmembraneandcatalystlayers.Second,amodelbasedonempiricaldataforvoltagedecayrates.Theapproachesareillustratedinfigure1.Thisworksuggestsawaytoconstructsuchamodelandgives first indications on whether certain operation parameters such as temperature and input current affect celldegradation.Basedontheapplication,operationcanbeoptimizedaccordingtothesimulationoutcomes.

Figure18:Mechanisticapproach(l.)andempiricalapproach(r.)

References:

Chandesris,M.etal.,2015.MembranedegradationinPEMwaterelectrolyzer:Numericalmodelingandexperimentalevidenceoftheinfluenceoftemperatureandcurrentdensity.InternationalJournalofHydrogenEnergy,40(3),pp.1353–1366.

LifetimeModel

Membrane•Thinning• LossofConductivity

CatalystLayers• LossofECSA

CurrentDistributor/BipolarPlates•Corrosion• Passivation


164

AbstractNo.227

AnalysisofPorousTransportLayersforProtonExchangeWaterElectrolysis

TobiasSchulera,ThomasJ.Schmidta,b,FelixN.BüchiaaElectrochemistryLaboratory,PaulScherrerInstitut,CH-5232Villigen-PSI,Switzerland

bLaboratoryofPhysicalChemistry,ETHZürich,CH-8093Zürich,[email protected]

Summary.Thestudyfocusesontheimpactofporoustransportlayers(PTL)ontheperformanceofprotonexchangewaterelectrolysis(PEWE).PropertiesoftitaniumbasedPTLsarecharacterizedbyX-raytomographyusingamicroCT.Furthermoreperformancetestsareconductedtoenableacorrelationwithex-situbasedPTLsstructureanalysis.

Abstract. Electrochemicalproductionofhydrogenhasbeen investigated foroveracentury.Stateof theartprotonexchangewaterelectrolyzereachesamaximumvoltageefficiencyof82%HHV[1].Thehighefficiency,asthesustainableand dynamic operation makes PEWE a suitable technique to face the global energy demand and environmentalproblemsofthesedays.

Theminimizationofpotential losses inPEWE is theessential requirement fordesigningefficientsystems.Themainlosseswithinanelectrolysercanberelatedtokinetic,ohmicandmasstransportlosses.Incontrarytokineticandohmiclosses,theoriginofmasstransportlossesisstillnotfullyunderstood.Morefundamentalstudieshavetobeconductedtoisolatethegoverningresistanceforthetwophasetransportinthecell.

Apossiblesourceistheporoustransportlayer.TheanodicporousmediaisingeneralbasedonTisubstructuressuchasfibresorparticlesenablingthewaterandgasmanagementbetweenthecatalyst layerandflowfieldsandprovidingthermalandelectricalconductivity. It isknownthatthemorphologyofPTLsaffectstheperformanceofPEWE.ThisstudyfocusesonthelinkbetweenPTLparametersanalysedbytheex-situmethodX-raytomographicmicroscopy(XTM)andperformancemeasurements.DifferentPTLtypesareanalysedtoisolatethegoverningparametersforPEWEs.

[1]M.Carmo,D.L.Fritz,J.Mergel,D.Stolten,AcomprehensivereviewonPEMwaterelectrolysis,InternationalJournalofHydrogenEnergy,38(2013)4901-4934.

Figure19.ImageA)shows1000x2000μmCT-sliceofafibrebasedTiPTL.The3DstructureofthesegmentedPTLisvisualizedinimageB);bothfeaturingavoxeledgelengthof2μm.

A) B)


165

AbstractNo.228

Plasma-chemicaltechnologiesforPEMelectrolyzerscatalystsandprotectivecoatings

VladimirFateev,OlgaAlexeeva,SergeyNikitin,VladimirPorembskiyNationalResearchCenter«KurchatovInstitute»,pl.Kurchatova,Moscow123182,Russia

[email protected]

Summary.Physical-plasma-chemicaltechnologiesweredevelopedforcatalystsandprotectivecoatingssynthesis.Anodeandcathodecatalystwithparticlessize2-20nmwithhighactivityandstabilitywereobtained.Protectivecoatingswithdifferentstructureandspecificsurfacedemonstratedtheirefficiencyathighoperatingpressure.

Abstract.Physical-plasma-chemicaltechnologies(ionimplantationandmagnetronsputtering)weredevelopedforcatalystsandprotectivecoatingssynthesis.NanostructuralPt-basedelectrocatalysts(Pt,Pd,Pt-Pd,Pt-Ni,Pd-Nionnanostructuredcarboncarriers)withcatalystparticlesdimensions2-10nmonnanostructuredcarboncarriersweresynthesizedforelectrolyzercathodes.Averageparticlesizecouldbeeasiervariedduetoioncurrentdensity,pulsedmodeofsputteringandtimeofsputtering.Ptcatalystwithaverageparticlesizeabout4-6nm(specificsurfaceupto60m2/g)demonstratedsameactivityatlowerPtloadingsascatalystssynthesizedbytraditionaltechnology–liquidphasereductionbyboronhydrideorethyleneglycol.Pt-Pd,Pt-Nidemonstratedthesameandevenhigher(Pt-Ni)activitybutaftersomeadditionalanodepolarization.AsanodecatalystIroxideandmixedRu-Iroxidesdepositedoncarbonparticlesbythesametechnologieswithfurthercarbonremovalbyoxidationinairatelevated(300-400oC)wereused.Inthiscaseparticlesizewaslarger(8-20nm)duetothermaltreatment.Suchcatalystshadhigherspecificsurfaceandactivityincomparisonwiththecatalystsofthesamecompositionobtainedbythermaldecompositionoftheproperprecursors.Oxygenevolutioncatalystsbaseonmixedoxidesdemonstratedhighactivity(sameactivityasforiridiumandevenhigher)withdecreased(about30%)ofIrloadingincaseofIr-Ruoxidesandgoodstability(testsduring500hours).

Magnetron-ionsputteringofPtandPdwasalsousedforbipolarplatesandelectrolyzercurrentcollectorsprotectionfrom oxidation and hydrogen saturation (for titanium components). Different sputtering modes (sputtering at aconstant current, sputtering at a constant current with pulsed negative potential bias of the sputtered currentcollector/bipolarplateandpulsedsputteringatlowfrequenciesweretested.Itwasdemonstratedthatcoatingswithdifferentstructure(density,porosityandsoon)couldbeobtainedatdifferentsputteringmodes.Forprotectivecoatingsthe sputtering at a constant current with pulsed negative potential bias (50-100 V) of the sputtered currentcollector/bipolarplatepermittedtogetthemostdenseandstablecoating.Thepulsedsputteringatlowfrequenciespermitted to get coatings with a high specific surface (roughness factor more than 20 in case of porous currentcollectors).Thecombinationofthetwomodesmentionedabovewasveryefficientforproductionofcurrentcollectorswith good stability and an increased surface catalytic activity. Such an activity permitted to decrease the cathodecatalystloadingfor20%.

ApplicationofcurrentcollectorswithhighspecificPtsurfacealsoprovidedanefficienthydrogen-oxygenrecombinationatanode (hydrogenwasdiffused fromcathode)atelevatedoperatingpressure (up to150bar). Theefficiencywascomparablewithmodificationof the anode catalyst compositionbyPt nanoparticles and resulted inoxygenpurityincrease(forexamplefrom96-97%to97-98%at130bar)ashydrogenreactionwithoxygenwasratherefficientatthecurrent collector surface. It was shown that Pt dissolution from anode protective coating is one of he reasons ofelectrolysiscelldegradationandadditional ion implantationbyAr ionspermittedto increasetheprotectivecoatingstabilityabout2times.

Acknowledgements.ThisresearchwasexecutedwithfinancialsupportoftheRussianScientificFoundation(projectNo.14-29-00111)inNRC“KurchatovInstitute”.


166

AbstractNo.229

ModifiedNiO/GDCcermetsaspossiblecathodeelectrocatalystsforH2Oelectrolysis&H2O/CO2co-electrolysisprocessesinSOECs

E.Ioannidoua,b,Ch.Neofytidisa,b,S.G.NeophytidesaandD.K.NiakolasaaFoundationforResearchandTechnology,InstituteofChemicalEngineeringSciences(FORTH/ICE-HT),GR-26504

Patras,GreecebDepartmentofChemicalEngineering,UniversityofPatras,GR-56504,Greece

[email protected]

Summary.Thepresentworkdealswithphysico-chemicalcharacterizationofcommerciallyavailableNiO/GDCpowder,modifiedwithAu,MoandBaO.SelectedelectrodeswerekineticallystudiedfortheRWGSreaction.Finally,singleSOECmeasurementswerealsoperformedinordertoinvestigatetheirperformancefortheH2Oelectrolysisprocess.

Abstract.H2Oelectrolysis constitutes a promisingmethod for the production of pure-H2 andO2 by using electricalenergy.Onecharacteristicandrecentapplicationofthistechnologyiselectrolysisathightemperatures,byusingSolidOxideElectrolysisCells(SOECs).Specifically,theelectricalenergythatisrequiredforthehightemperature(600-1000oC)H2Oelectrolysisprocess,ismuchlowerthantheenergyrequiredatlowtemperatures(<100oC),whichasaresultyieldssignificantlyhigherefficiencyandperformanceintheformercase[1].Althoughthistechnologicalapplicationhasconsiderableadvantages,itconfrontsmanyproblemsthatpreventthewidespreaduseandcommercialization.Oneofthemostimportantisthedeactivationofthefuelelectrodes(H2O/H2),whichisusuallyascribedtonickelre-oxidationand/oragglomerationduringH2Oelectrolysis,or/andcarbondepositionduringH2O/CO2co-electrolysis [2].Anotherdisadvantageisthedegradation/delaminationoftheoxygenelectrodes.Consequently,recentresearchactivitiesfocusonthedevelopmentand investigationofnew,tolerantfuel (H2O/H2)andairelectrodes.Theaimofthiswork isthedevelopment and study of ceramo-metallic electrocatalysts/electrodes, which are based on commercial NiO/GDCpowder(MarionTechnologies).ThispowderismodifiedwithchemicalmethodsbytheadditionofBa,Auor/andMo.TheAuor/andMomodifiedelectro-catalystshavebeenextensivelystudied,fromourresearchgroup,aselectrodesinSolidOxideFuelCells(SOFCs)applications[3,4]andtheiruseinSOECs,asH2/H2Oelectrodes(cathodes),isalsoveryinteresting.Furthermore,themodificationwithBaaimstotheprotectionoftheNiproperties,towardsthepotentiallimitation of fast re-oxidation or/and agglomeration. All cermets were investigated through physicochemicalcharacterization with the methods of BET, XRD, XPS, TGA-MS, H2-TPR, O2-TPO, including specific redox stabilitymeasurementsundervariousH2O-H2feedconditions.Thepowderswerealsousedforthepreparationofappropriatepaste, which was deposited on solid YSZ electrolytes with the method of screen printing. The prepared/calcinedelectrodeswerekineticallystudied,intheformofhalfcells,fortheircatalyticactivityfortheReverseWaterGasShiftReaction in the temperature range of 800-900 oC with simultaneous analysis of products/reactants using gaschromatography. Electrocatalytic measurements with Electrochemical Impedance Spectra (EIS) analysis were alsoperformedinsinglesolidoxidecells,withinthesametemperaturerange,underH2OelectrolysisconditionsbyapplyingdifferentpH2O/pH2ratios.

Acknowledgments.TheresearchleadingtotheseresultshasreceivedfundingfromtheFuelCellsandHydrogen2JointUndertakingundertheprojectSElySOswithGrantAgreementNo:671481.This JointUndertaking receives support from theEuropeanUnion’sHorizon2020ResearchandInnovationProgrammeandGreece,Germany,CzechRepublic,France,andNorway.References.[1]M.A.Laguna-Bercero,J.PowerSources203(2012)4-16.[2]P.Moçoteguy,A.Brisse,InternationalJ.HydrogenEnergy38(2013)15887-15902.[3]D.K.Niakolas,M.Athanasiou,V.Dracopoulos, I.Tsiaoussis,S.BebelisandS.G.Neophytides,AppliedCatalysisA:

General456(2013)223-232.[4]C.Neofytidis,M.Athanasiou,S.G.Neophytides,D.K.Niakolas,TopicsinCatalysis,58(2015)1276-1289.


167

AbstractNo.230

InoperandoRamanspectroscopyforinvestigationofsolidoxideelectrolysiscells

MarieLundTraulsena,R.A.Walkerb,PeterHoltappelsaaTechnicalUniversityofDenmark,DepartmentofEnergyConversionandStorage,

bMontanaStateUniversity,[email protected]

Summary. How can in operando Raman spectroscopy increase our understanding of degradation and activationprocesses in solidoxideelectrolysis cells?Recentexperimental resultsare reported, includingexperiments showingremarkablepolarisationinducedcompositionalchangesininfiltratedperovskiteelectrodes.

Abstract. Traditional evaluation of solid oxide electrolysis cell (SOEC) durability and performance relies onelectrochemicalmethodsincludingvoltammetryandimpedancespectroscopy.Inoperandoelectrochemicalstudiesarethenfollowedbypostmorteminvestigationsofchangesinmicrostructureandelementalcomposition.Asasupplementto these well-established characterization methods various in situ and in operando spectroscopies have receivedincreasedattention in the solidoxide cell communityduring the lastdecades1-2andmayofferagreatpotential forimprovingtheunderstandingofdegradationprocessesinsolidoxideelectrolysiscells.Theadvantageoftheseinsituandoperandotechniquesistheymayrevealchangesinelementalelectrodecompositionsinrealtimeasthechangesoccur.

For solid oxide cells in operando spectroscopy is defined as spectroscopywith the three operating parameters: 1)Temperature, 2) Atmosphere and 3) Electrical polarization, held at values similar to those experienced during realoperationofthecells.PreviousworkusingoperandoRamanspectroscopytostudysolidoxidecellsandmaterialshasexamined cokingby carbon containing fuels3 aswell as changes in amaterial’s oxidation state4 under atmosphericpressuresandattemperaturesashighas800°C.

Inthepresentposter,anumberofrecentcasesarepresented,whereRamanspectroscopyhasbeenappliedinsituandinoperandotostudysolidoxidecellsandsolidoxidematerials.SpecialemphasisisputonanexperimentapplyinginoperandoRamanspectroscopyonanairelectrodepreparedbyBaOinfiltrationofLSM((La0.85Sr0.15)0.9Mn3±j), asthisexperimentledtoseveralinterestingobservations5.ThefirstsurprisingdiscoverywasthattheBaOhadformedasecondaryBa3Mn2O8phaseduetoreactionwiththeLSM.ThisphasewaslikelythecauseofadecreasedpolarizationresistanceobservedatOCVconditions.Secondly,thisBa3Mn2O8phasereversiblydecomposedwithelectricalpolarizationwithMnchangingitsoxidationstatesequentiallyfrom5+to2+(MnO).Whentheelectricalpolarizationwasremoved,theMnOwastransformedbackintoBa3Mn2O8.Thesefindingsemphasizetheneedtodirectlyobservematerialchangesinhightemperaturesolidoxideelectrodesunderrealisticworkingcondition,especiallyelectrodespreparedbyinfiltration.

[1]M.B.Pomfret,J.C.Owrutsky,R.A.Walker,Annu.Rev.Anal.Chem(2010)3pp.151-174

[2]M.L.Traulsen,C.Chatzichristodoulou,K.VelsHansen,L.TheilKuhn,P.Holtappels,M.B.Mogensen,ECSTrans.(2015)66(2)pp.3-20[3]M.B.Pomfret,J.Marda,G.S.Jackson,B.W.Eichhorn,A.M.Dean,R.A.Walker,J.Phys.Chem.C(2008)112pp.5232-5240[4]R.C.Maher,L.F.Cohen,P.Lohsoontorn,D.J.L.Brett,N.P.Brandon,J.Phys.ChemA(2008)112pp.1497-1501[5]M.L.Traulsen,M.D.McIntyre,K.Norrman,S.Sanna,M.B.Mogensen,R.A.Walker,Adv.Mater.Interfaces(2016)1600750


168

AbstractNo.231

OxygenevolutionreactionkineticsonLSMelectrodedopedbyPt

MartinPaidara,DanielBudáča,FilipKarasa,RomanKodýma,KarelBouzekaaUniversityofChemistryandTechnology,Prague

[email protected]

Summary: LSM is proven electrode material for oxygen electrode in the high temperature water electrolysis. Itselectrocatalytical activity can be promoted by addition of platinum. Various level of Pt loading was evaluated insymmetricalcell.

Abstract.Hightemperaturewaterelectrolysisrepresentsintensivelystudiedtechnology.Incontrasttothewell-knownestablished technologies, like alkaline and PEM water electrolysis, the high operating temperature brings severaladvantages. The main of them are lower reversible cell voltage, fast electrode reactions kinetics and their highreversibility.Thereforebothoperatingmodes,i.e.fuelcell(SOFC)andelectrolysis(SOEC),arepossiblewiththesameunit.Itmakeshightemperatureelectrolysisattractivewayforbufferingthefluctuationofelectricenergyproductiongeneratedby alternativepower sources.Although significantprogresswasmadeduring last decade, several issuesremainstillunresolved.Themainofthemisdurabilityofthesystem.Theundesiredmorphologychangesofelectrodes,formationofinactivecompoundsandlayersdelaminationcanbementionedastypicalexamples.

Non-stoichiometricoxideswithperovskitestructureareusuallyusedasoxideelectrode.MostwidelyusedmaterialisLaMnO3dopedwithSr,whichistypicallyreferredtoasLSM.Besideelectronconductivityithasalsoionicconductivity.Butionicconductivityisratherpoor.AnotherdrawbackofpureLSMastheoxygenelectroderepresentsitsinsufficientmechanicalstabilityanditspotentialdegradationatthephase interfacewithY-stabilizedZrO2(YSZ)electrolyte. It istypicallydueto itsdelamination.Therefore,LSMispreferablyused inamixturewithYSZ(orother ionicconductingmaterial) inorder tomaximizeoccurrenceof the threephaseboundary in theelectrodebody.At the same time itimprovesmechanicalstabilityoftheelectrodeanditsadhesiontotheelectrolytesurface.TheoptimalratiobetweenYSZandLSMiscrucialforproperoxygenelectrodeperformance.

Beside the non-stoichiometric oxides, the platinummetal catalyst is accepted as the best catalyst for SOFC/SOEC.Platinumpossessesseveralimportantadvantages,likeitdoesn’ttendtoformnonconductivecompoundsonthephaseinterfaces. Themost importantdrawback is, however, itshighprice. The compromise is theuseof LSMwith smalladditionofplatinumforenhancingcatalyticproperties.Asitwasfoundbyseveralauthors[1,2],additionofalready0.5wt.%oftransitionmetalsintothecathodeenhancestheSOFCperformancesignificantly.LowcontentofPtensureshigherPtutilizationincomparisontothelowtemperaturePEMsystems.

PresentworksdealswithdeterminationofinfluenceofthePtadditiontotheLSMontheresultingelectrodeproperties.SynthetizedPtpowderwasaddeddirectlytotheLSM/YSZmixture.LSM/YSZratiowaskept50:50inallexperiments.Prepared electrode mixtures were deposited by screen printing on the YSZ substrates and sintered at 1150°C.SymmetricalcellbasedonLSMelectrodesonbothsidesoftheelectrolytewereprepared.Thesymmetricalcelloperatedin oxygen pump mode. Impact of the oxygen partial pressure and operational temperature were studied. Cyclicvoltammetryandelectrochemicalimpedancespectroscopy(EIS)wereusedtocharacterizethesystem.TheIRcorrectedcurveswerefittedbyone-dimensionalmacrohomogeneousmodelofsingleSOECcelltoobtainrealkineticsparametersof the electrode. Exchange current density and charge transfer coefficient was determinedwith respect to the Ptcontent.

Acknowledgement:TheauthorsacknowledgethefinancialsupportoftheFuelCellsandHydrogenJointUndertakingwithinaframeworkoftheSElySOsProject,contractNo:67148.

[1]R.J.Gorte,J.M.Vohs,Annu.Rev.Chem.Biomol.Eng.,2(2011)9-30.[2]S.Guo,H.Wu,F.Puleo,L.F.Liotta,Catalysts,5(2015)366-391.


169

AbstractNo.232

Experimentalloopofhightemperatureelectrolysisincouplingofhightemperatureprocess

Ing.MartinTkáča,b,Dr.-Ing.KarinStehlíkaaCentrumvýzkumuŘežs.r.o.,Hlavní130,Řež,25068,CzechRepublic

bUniversityofChemistryandTechnologyPrague,,Technická5,16628Prague6,[email protected]

Summary.EuropeanUnionwantstheenergysectortobeshiftedtowardsthelow-carbontechnologies(H2,renewableenergy).WhenH2willbeusedinwiderscale(energetics,mobility),itsproductiononlyfromelectricitysurpluswillnotbesufficientandacentralH2productionwillbenecessary.Therefore,theHT-electrolysisincogenerationwithotherprocessesisinvestigatedinCentrumvýzkumuŘež(CVŘ).

Abstract.

High-temperatureelectrolysisisespeciallyprofitablewhenthewasteheatisused.Thisheatcanbeproducede.g.bytheplannedfourth-generationnuclearreactor,socalledhigh-temperaturegasreactor(HTGR).HydrogenproductionwithHTGRthatcanproducealargeamountofhydrogencouldbeoneofthepromisingsystemsforafuturehydrogeneconomy, but HTGR reactor is not yet available. Therefore, the paper investigates the co-generation of high-temperatureelectrolysiswiththeindustrially-availabletechnologies.

WithinthesustainableEuropeanprojectSUSEN,SUStainableENergy,anexperimentalfacilityforhydrogengenerationbyhigh-temperaturewaterelectrolysis(HTE)wasbuilt.Theobjectiveoftheloop(fig.1)istoexperimentallyvalidatethethermodynamic coupling of HTE with HTGR (high temperature gas-cooled reactor) and other high temperatureprocesses.Thecentralcomponentistheheatexchangerforgasandwatersteam.Thegassideoftheheatexchangersimulates a high-temperature process. It is also possible to test the combination with different high-temperatureprocesses,e.g.heatfromsteelfabrication,refinery,pyrolysisandotherindustrialprocesses.Thetestwillbeconductedonapprox.1kWelelectrolysisstack.

Fig.1:schemeofHigh-temperatureelectrolysisloop

Acknowledgement

ThepresentedworkwasfinanciallysupportedbytheMinistryofEducation,YouthandSportCzechRepublicProjectLQ1603(ResearchforSUSEN).ThisworkhasbeenrealizedwithintheSUSENProject(establishedintheframeworkoftheEuropeanRegionalDevelopmentFund(ERDF)inprojectCZ.1.05/2.1.00/03.0108).


170

AbstractNo.233

Distributionofrelaxationtimes–toolfortheanalysisofimpedancespectra

JustynaBartoszek1,JakubKarczewski2,Yi-XinLiu3,Sea-FueWang3andPiotrJasinski11FacultyofElectronics,TelecommunicationsandInformatics,GdańskUniversityofTechnology,Gdansk,Poland

2FacultyofAppliedMathematicsandPhysics,GdańskUniversityofTechnology,Gdansk,Poland3InstituteofMaterialsScienceandEngineering,NationalTaipeiUniversityofTechnology,Taiwan,R.O.C.

[email protected]

Summary.InthisworkusefulnessofDRTanalysiswillbediscussed.

Abstract. Impedance spectroscopy is a standard tool for investigation of electroceramic devices like fuels cells orelectrolyzers.Itallowsinvestigatingohmicandpolarizationresistancesandpotentiallylinkthepolarizationresistancewith the limiting electrochemical process. However, frequently the electrochemical processes have very similarcharacteristicfrequencyandpointingtheexactprocessisverychallenging.Therefore,recentlyadistributionofrelationtimes(DRT)isusedtoanalyzetheimpedancespectraandbetterseparatetheprocesses[1,2].Thisanalysisisespeciallyusefulfortheanalysisofsolidoxideelectrolyzercells(SOECs),forwhichmorethan6electrochemicalprocessescanbeforeseen.Although,theanalysisisrathercomplicated,analysistoolsstarttobeavailableon-line[3].

InthisworkusefulnessofDRTanalysiswillbediscussed.Especially,thelimitationofDRTanalysiswillbepointedandissuesrelatedtodatadiscretizationandselectionofDRTparameterswillbeanalyzed.TheexamplesofDTRanalysiswillbeprovidedandconnectedwithexactDRTsolutionsofstandardelectrochemicalprocesses.Thedatawillbelinkedwithresultsobtainedonsolidoxideelectrolyzers.IssuesrelatedtopolarizationresistanceanalysisbasedonDRTplotwillbediscussed.

Acknowledgement:

Thisworkwassupportedbythe2ndPolish-Taiwanese/Taiwanese-PolishJointResearchProjectDZP/PL-TW2/6/2015-InnovativeSolidOxideElectrolyzersforStorageofRenewableEnergygrantedbytheNationalCentreforResearchandDevelopmentofPolandandMinistryofScienceandTechnologyofTaiwan.

References:

[1] B.A.Boukamp,Fouriertransformdistributionfunctionofrelaxationtimes;applicationandlimitations,Electrochim.Acta.154(2015)35–46.doi:10.1016/j.electacta.2014.12.059.

[2] B.A.Boukamp,A.Rolle,AnalysisandApplicationofDistributionofRelaxationTimesinSolidStateIonics,SolidStateIonics.(2016).doi:10.1016/j.ssi.2016.10.009.

[3] F.Ciucci,C.Chen,AnalysisofElectrochemicalImpedanceSpectroscopyDataUsingtheDistributionofRelaxationTimes:ABayesianandHierarchicalBayesianApproach,Electrochim.Acta.167(2015)439–454.doi:10.1016/j.electacta.2015.03.123.


171

AbstractNo.234

In-situupgradingofbio-oilusingsolidoxideelectrolysisprocess

S(Elango)Elangovana,InsooBaya,DennisLarsena,EvanMitchella,JosephHartvigsena,ByronMilleta,JessicaElwella,MukundKaranjikarb,PieterBillenc,SabrinaSpataric,YetundeSorunmuc,DanielSantosad,and

DouglasElliottd

aCeramatec,Inc.,SaltLakeCity,UT,USAbTechnologyHolding,LLC,SaltLakeCity,UT,USA

bDrexelUniversity,Philadelphia,PA,USAcPacificNorthwestNationalLaboratory,Richland,WA,USA

[email protected]

Summary.Bio-oilfromfastpyrolysisofwoodybiomassisapotentialsourceofgreenfuel.Presently,bio-oilrequirescentralizedhydrodexoygenationprocesstoloweritshighoxygencontentbutinstabilityofbio-oilmakesitachallengefor storage and transportation. A partial or full deoxygenation process using solid oxide electrolysis process ininvestigatedasapotentiallowcost,lowCO2footprintalternative.

Abstract.Biomasscanbeconvertedtoliquidfuelsviabio-oilproductionbyfastpyrolysis.Typicalpyrolyzeroperationproducesbio-oilasamixtureofoxygenatedorganiccompoundsandisbiphasic.Onlytheorganicphaseisprocessedbyhydrodeoxygenation,leavingbehindvaluablecarbon-containingmaterialintheaqueousphase.

Bio-oilpropertiessuchaslowheatingvalue,incompletevolatility,acidity,instability,andincompatibilitywithstandardpetroleumfuelssignificantlyrestrictitsapplication.1Theundesirablepropertiesofpyrolysisoilresultfromthechemicalcompositionofbio-oilthatmostlyconsistsofdifferentclassesofoxygenatedorganiccompounds.Theeliminationofoxygen is thus necessary to transform bio-oil into a liquid fuel that would be broadly accepted and economicallyattractive.Hydrodeoxygenation (HDO)orhydrotreating involveshigh-temperature,high-pressureprocessing in thepresence of hydrogen and catalyst to remove oxygen.2 HDO suffers from significant challenges such as coking,polymerizationofvariouscompoundsinbio-oilbeforedeoxygenation,deactivationofHDOcatalystsbythepresenceofwaterinthepyrolysisoil,requirementofsignificantquantitiesofhydrogentoremoveoxygen,economicavailabilityofhydrogenatdistributedsmaller scale suitable forbiomassconversionandsignificantprocessexothermdue tohighoxygenremovalrequirement(25%bymass).Thus,therearenumerouschallengesthatpreventcommercializationofbio-oil upgrading to hydrocarbons process. An alternative economically feasible, less hydrogen dependent anddecentralizedprocessisrequiredtoconvertbio-oiltorefineryreadyhydrocarbons.

A process of deoxygenation of bio-oil using solid-state, oxygen conductor based electrochemical cell is underinvestigation.Thecell isoperatedat500–550°C tomatch the typicalpyrolysis temperature forbothphysicalandprocess integration of the two operations. The electrolysis process removes oxygen from the oxygenated organicmolecule aswell from steam to produce hydrogen in-situ. Thus, relatively small quantities of external hydrogen isneeded for deoxygenation, allowing for a distributed, small scale integrated upgrading unit. Mixtures of modelcompoundsweretestedusingbuttoncellsandshortstacks.Theproductfromtheelectrochemicalcellcontainedasuiteof compounds with significantly lower oxygen content. Integrated testing of short stacks at the Pacific NorthwestNationalLaboratoryusingaslipstreamfromthepyrolyzershowsthattheproductcompositionissimilartocatalyticpyrolysisprocess.Additionaltestsareplannedusingimprovedelectrodematerials.

1S.Czernik,A.V.Bridgwater,Energy&Fuels18(2004)590–598.

9E.Tronconi,N.Ferlazzo,P.Forzatti,I.Pasquon,B.Casale,L.Marini,Chem.Eng.Sci.1992,47,2451.

Acknowledgment:ThismaterialisbaseduponworksupportedbytheDepartmentofEnergyunderAwardNumberDE-EE0006288.


172

AbstractNo.235

InfiltratedSolidOxideCellOxygenElectrodes:DegradationDuringReversibleCurrent-SwitchingOperation

MatthewLua,JustinRailsbacka,andScottABarnettbaDepartmentofMaterialsScience&Engineering,NorthwesternUniversity,Evanston,ILUSA

[email protected]

Summary.Wereport results showinggood stabilityof symmetrical solidoxidecellsoperated reversiblyat1Acm-2,utilizingelectrodematerialsproducedbyinfiltrationofthemixed-conductingoxides(Sm,Sr)CoO3(SSC)intoGd-dopedCeria(GDC)andLa2NiO4(LNO)into(La,Sr)(Ga,Mg)O3(LSGM)scaffolds.

Abstract.Manypriorstudieshaveshownthatsolidoxidecells(SOCs)withLSM-basedoxygenelectrodesdegradeduringelectrolysisorreversingcurrentoperationatsufficientlyhighcurrentdensityand/orelectrodeoverpotential.Reductionintheelectrodeoverpotential,atagivencurrentdensity,isonewaytoreducethehigheffectiveoxygenpressureattheelectrode/electrolyteinterface.Itmayalsobeusefultoreducethecelloperatingtemperature,sincethiswillreducecationtransportkinetics thatenabledegradationby,e.g.,void formationonelectrolytegrainboundaries. Reducedoverpotential and/or reduced temperature can be enabled through the use of mixed-ionically- and electronically-conducting(MIEC)electrodessuchas(La,Sr)(Fe,Co)O3(LSCF).Furtherimprovementsarepossiblebyutilizingnano-scaleMIECelectrodes,suchasthoseobtainedbywet-chemicalinfiltration.

Herewereportreversiblecurrent-switchinglifetestresultsonsymmetricalcellswithelectrodespreparedbyinfiltrationofMIECmaterialsintoporousionically-conductingscaffolds.Twocelltypesarereported–theperovskite(Sm,Sr)CoO3(SSC)infiltratedintoaporousGd-dopedCeria(GDC)scaffoldwithGDCelectrolyte,andtheRuddlesden-PopperphaseLa2NiO4(LNO)infiltratedintoaporous(La,Sr)(Ga,Mg)O3(LSGM)withLSGMelectrolyte.Lifetestscarriedoutat650oCinair,withthecurrentdensityof1.0or2.0Acm-2switchedabruptlyevery6h,foracycleperiodof12h.Eachlifetestwasrunfor~1000h,i.e.,~80completecycles.Impedancespectroscopymeasurementsweretakenperiodicallyatzerocurrent.At1.0Acm-2,correspondingtoaninitialelectrodeoverpotentialof~__V,bothcellsshowedacontinuousbutrelativelylowdegradationrateof__%/kh.At2.0Acm-2,correspondingtoaninitialelectrodeoverpotentialof~__V,bothcellsshowedcontinuousbutmuchlargerdegradationatarateof~__%/kh.Theincreaseincellresistancewasapproximatelyequallysplitbetweentheelectrolyteandtheelectrodeineachcase.Post-measurementevaluationofthecellsusingscanningelectronmicroscopyshowednoobviousmicrostructuralchanges,evenatthehighercurrentdensity.ResultsonSrsegregationmeasurementswillbereportedfortheSSCelectrodes.


173

AbstractNo.236

Protectivecoatingsforinterconnectsforsolidoxidecellstacks

SebastianMolin,MingChenandPeterVangHendriksen

DepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,Roskilde,[email protected]

Summary.Longtermoperationofsolidoxidecellstackswithlowdegradationrequiresuseofprotectiveinterconnectcoatings with low chromium permeation and high electrical conductivity. This work summarizes research anddevelopmenteffortsinthefieldofprotectivecoatingscarriedoutatDTUEnergy.

Abstract.Hightemperaturecorrosionofsteelinterconnects(IC)isanimportantdegradationissueofsolidoxidecellstacks.Duetoacontinuousgrowthofrelativelypoorlyconductiveoxides,resistanceoftheinterconnectincreasesovertime[1],contributingtoincreasingstacklosses.Inaddition,ontheoxygensideoftheIC,evaporationofCrspeciescanoccurandpoisontheelectrodesfurtherloweringstackperformance.Onthehydrogenside,interdiffusionofCr,FeandNicanoccurandcauseaustenitization[2,3]ofthealloyandchangeofitsthermalexpansionandcarbonsolubility.Formitigation of these negative phenomena protective coatings can be used. Thiswork summarizes coating solutionscurrentlyusedatDTUEnergy.

Fortheoxygenside,protectivecoatingsincludeMn-Cospinels,whichhavebeenproventoblockchromiumdiffusion,havehighelectronic conductivity andgood thermal expansion coefficientmatch toother stack components. Thesecoatings,typically~10µmthick,arepreparedbytheelectrophoreticdepositionmethod,allowingcoveringlargeshapedICs.Inadditiontothespinel,thinreactiveelementscoatingsbasedprimarilyonyttriaareconsideredforevenfurtherlowering corrosion rates.Whenused togetherwith the spinel, these coatings offer synergistic effect of slowoxidegrowthandlowCrdiffusionontheoxygenside.

Forthehydrogenside,coatingsbasedonyttriaanddopedceriaarebeingconsidered.Theycanslowtheoxidegrowthandblockinterdiffusionbetweenthealloyandthehydrogenelectrode.

Bycombiningcoatingsbothfortheoxygensideandforthehydrogenside,anadvancedandeffectivecoatingsolutioncanbeachieved.

References:

[1] S.Molin,P.Jasinski,L.Mikkelsen,W.Zhang,M.Chen,P.V.Hendriksen,LowtemperatureprocessedMnCo2O4andMnCo1.8Fe0.2O4aseffectiveprotectivecoatingsforsolidoxidefuelcellinterconnectsat750°C,J.PowerSources.336(2016)408–418.

[2] S.Molin,M.Chen,J.R.Bowen,P.V.Hendriksen,Diffusionofnickelintoferriticsteelinterconnectsofsolidoxidefuel/electrolysisstacks,ECSTrans.57(2013)2245–2252.

[3] M.Chen,S.Molin,L.Zhang,N.Ta,P.V.Hendriksen,W.-R.Kiebach,etal.,ModelingofNiDiffusionInducedAusteniteFormationinFerriticStainlessSteelInterconnects,ECSTrans..68(2015)1691–1700.


174

AbstractNo.237

PowertoGas/Liquid-biomassgasificationandSOECcombinedsystem

ShahidAlia,KimSørensena,andMadsP.Nielsena

aDepartmentofEnergyTechnology,AalborgUniversity,Denmark

sal@et.aau.dkSummary.Averypromisingroutefortheproductionofbiomass-derivedtransportfuelcanbeobtainedbycombininggasificationandelectrolysisunitswithafuelsynthesisreactor.Themethanolormethaneproducedinthiswaycouldbe120-170%ofthebiomassinputenergy[1,2]

Abstract.Manydifferenttechnologieshavebeenconsideredforlarge-scalestorageofrenewableelectricitye.g.hydrostoragewhichistechnicallyverymaturebutlimitedpossiblesites.Electrochemicalstorageisalsopossiblebutbatteriesareverybulky,expensiveandhavelimitedoperationallife.Thenthereischemicalenergystorageintheformofhydrogen.Hydrogenproductionisanotheroptionwhichhasunlimitedproductionprospectandcanbeconvertedbacktoelectricityusingfuelcell(thoughnotpreferredbecauseofverypoorround-tripefficiency).Itcanbeusedasavaluablefeedstockforchemicalindustrye.g.productionofammonia,ethyleneandsynthesisofalternativeenergycarrierssuchasSyntheticnaturalgas(SNG),methanol,Dimethylether(DME)etc.bycombiningwithCO2andN2.Thisadditionofexternalhydrogenwillupgradetheexistingbiomassgasificationprocesstherebyextendingthebiomassresources.

TheoverallpurposeoftheSYNFUELprojectis“toproducesustainablefuels:Usingsurpluselectricityfrome.g.windpowertoproducehydrogenbysteamelectrolysisandupgradeittogasifiedbiomasstherebyextendingthebiomassresources.Bycombiningelectrolysisandthermalgasificationwithacatalyticconverteritbecomespossibletosynthesizemethane,SNGorliquidfuelsuchasDME,FT(Fischer-Tropsch)andmethanol”.Thehydrogenadditionmeetstherequiredstoichiometryandallowsanearlycompleteutilizationofthecarboncontainedinthebiomass[3].Anotheradvantageofsuchcombinedsystemis-theoxygenproducedintheelectrolysiscanbeusedinoxygen-blowngasificationprocesswhichhastheadvantageofavoidingfeedstockfromnitrogendilution[4].

AgasificationmodelofLT-CFB(Lowtemperaturecirculatingfluidizedbed)usingoxygenasgasifyingagentinsteadofairhasbeendeveloped,itisanovelmethodologyandhardlyanyexperiencewiththesesystemsexistinpractice.Similarly,amodelforsolidoxideelectrolysis(SOE)hasbeendevelopedandcombinedwithgasificationfortheproductionofbothmethanolandmethane.Differentanalyseshavebeenperformedonthecompletesystemmodele.g.Recyclerationeffectonthemethanation,temperatureandpressureeffectonsyngascompositionandfinalproductetc.Currently,workingontheSOEmodeltomodifyitforhigherpressures,comparestothealreadydevelopedstateoftheartsystemstomakeitmorecompatiblewiththegasificationprocessandespeciallyformethanolsynthesis.Later,thewholesystemwillbeoptimizedbyheatintegrationusingpinchanalysisandheatexchangernetworksynthesis.

References

1.LifeCycleAssessmentofanAdvancedBioethanolTechnologyinthePerspectiveofConstrainedBiomassAvailability.Hedegaard,Karsten,Thyo,KathrineA.andWenzel,Henrik.2008,EnvironmentScience&Technology,Vol.42,pp.7992-7999.

2.Breakingthebiomassbottleneckofthefossilfreesociety.Wenzel,Henrik:Concito,2010.

3.SynthesisofMethanolfromBiomass/CO2Resources.Specht,M.,etal.,etal.Amsterdam:s.n.,1999.GreenhouseGasControlTechnologies,p.723.

4.Reviewandanalysisofbiomassgasificationmodels.Puig-Arnavat,Maria,Bruno,JoanCandCoronas,Alberto.2010,RenewableandSustainableEnergyReviews,Vol.14,pp.2841-2851.


175

AbstractNo.238

LSCFandLSCinfiltratedLSCFelectrodeforhightemperaturesteamelectrolysis

VaibhavVibhu1,3,SaffetYildiz1,SeverinFoit1,KevinSchiemann1,I.C.Vinke1,R.-A.Eichel1,2andL.G.J.deHaart11InstituteofEnergyandClimateResearch,FundamentalElectrochemistry(IEK-9),ForschungszentrumJülichGmbH,

52425Jülich,Germany2InstituteofPhysicalChemistry,RWTHAachenUniversity,52074Aachen,Germany

3e-mailofcorrespondingauthor:[email protected]

Summary:ThepresentworkisfocusedonLa0.58Sr0.4CoO3-δ(LSC)infiltratedLa0.58Sr0.4Co0.2Fe0.8O3-δ(LSCF)electrodesforsolid oxide electrolysis cell (SOEC) aimed at efficient hydrogen production. In this respect, polarization curves andimpedancespectraofbothsymmetricalaswellassinglecellsarecomparedandinvestigatedindetail.

Abstract:Solidoxideelectrolysis cells (SOECs)haveattractedconsiderable interest in theattainmentofhighpurityhydrogenproduction.ThemostcommonelectrolyteandhydrogenelectrodematerialsforSOECareyttriastabilizedzirconia(YSZ)andNi-YSZrespectively,exhibitinggoodelectrochemicalperformanceandstability.Intermsofoxygenelectrode materials LSM, LSCF and their composite with GDC or YSZ have been reported. Nevertheless, theelectrochemical and thermo-mechanical stability of these materials during SOEC operation still requires furtherinvestigation.

RecentlyseveralresearchershavefocusedtheirworkonthedegradationmechanismduringSOECoperation.Inshortterm(duringfirstfewhours)ofageing,theformationofSr-and/orCo-richparticlesonthetopsurfaceofdenseLSCFsampleshasbeenreportedbytheauthorswhileonlysurfaceSr-enrichmentisusuallyobservedinagedporousoxygenelectrode without microstructural changes [1, 2]. When it is kept for long duration at operating condition thenparticularlythedelaminationofoxygenelectrodeattheelectrode/electrolyteinterfaceisthemostcommonmodeoffailure[3,4].AccordingtoVirkar[3],theoxygenevolutionreactionattheoxygenelectrodeleadstoalocallyhighpartialpressureofoxygen (pO2) in theelectrodeandat theelectrode/electrolyte interface inSOECmode, further leads toincrease inelectrodeoverpotential. So, thepO2andoverpotential (η) at theelectrode/electrolyte interfaceare thegoverningfactorsandshouldbetreatedcarefullyconsideringthespecificinterfacestructure.Onewaytoavoidtheseproblemscouldbetoincreasetheionicconductivityattheelectrode/electrolyteinterface.

Ourcurrentresearchwork is focusedontheoxygenelectrodetoavoidsuchkindofdelaminationby increasingtheactivity of oxygen electrode using infiltration of very active LSCmaterial. The electrochemical performance of LSCinfiltrated LSCF oxygen electrode is investigated for steam electrolysis and compared with blank LSCF electrode.Furthermoreitisalsotriedtoinvestigateatwhichoverpotentialthedelaminationofoxygenelectrodestarts.Inthisrespectthesymmetricalhalf-cellaswellassinglecellcontainingLSCFoxygenelectrodewithandwithoutLSCinfiltrationare characterized using electrochemical impedance spectroscopy in the temperature range 750-900 °C. Thesymmetricalhalf-cells“8YSZ//CGO//LSCF”arecharacterizedinathreeelectrodesetupusingareferenceelectrodewiththeaimtoobtaindetailedinformationonthedifferentelectrochemicalprocessesanddegradationmechanisms.Thepolarizationresistance(Rp)valuesobtainedforsymmetricalhalf-cellswithandwithoutinfiltrationare24mΩ.cm2and32mΩ.cm2 respectively, at 800 °C. Thebehavior ofNi-YSZ supported single cells “Ni-YSZ//8YSZ//CGO//LSCF is alsoinvestigatedfrom750-900°CtemperaturerangeunderbothSOFCandSOECmodes.Amaximumcurrentdensityvalueof1.48A.cm-2isobtainedat800°Cunderanappliedelectrolysisvoltageof1.5V.Moreover,adecreaseintheslopeofI-Vcurve isnoticedwhentemperature increasesfrom750to900°C,whichmeansthat lowerelectrolysisvoltage isrequiredforhydrogenproductionathighertemperature.TheinvestigationofLSCinfiltratedLSCFsinglecellisunderprogress. The comparison of electrochemical properties of symmetrical half-cells and single cellswith andwithoutinfiltrationwillbepresentedanddiscussedindetail.References[1]L.C.Baqué,A.L.Soldati,E,Teixeira-Neto,H.E.Troiani,A.Schreiber,A.C.Serquis,JournalofPowerSources,337

(2017)166-172.[2]J.Druce,I.Tatsumi,J.Kilner,SolidStateIonics,262(2014)893-896.[3]AnilV.Virkar,InternationalJournalofHydrogenEnergy,35(2010)9527-9543.[4]J.R.Mawdsley,J.D.Carter,A.J.Kropf,B.Yildiz,V.A.Maroni,InternationalJournalofHydrogenEnergy,34(2009)

4198-4207.


176

AbstractNo.239

UnderstandingandTailoringActivityandStabilityofPerovskiteandManganeseOxidesfortheOxygenEvolutionReaction

VladimirTripkovica,HeineA.Hansena,JuanM.G.LastraaandTejsVeggeaaDepartmentofEnergyConversionandStorage,TechnicalUniversityofDenmark,4000Roskilde,Denmark

[email protected]

Summary.Using density functional theory calculations we endeavour to understand and disentangle the complexinterplaybetweenmagnetic,electronicandgeometricfactorsandtheirinfluenceonthe:structurestability,electronicconductivityandcatalyticactivity.Exploitingthisknowledgeweidentifyseveralpromisingoxygenevolvingcatalysts.

Abstract.Theoxygenevolutionreaction(OER)isabottleneckindirectsolarandelectrocatalyticwatersplittingcells,andrechargeableaqueousmetal-airbatteries.Improvingthecost-efficiencyofthesedevicesrequiresdevelopmentofefficient and cheap oxygen evolving catalysts. A good catalystmaterial should fulfil several important criteria: thecompositionandstructureshouldbestableatconditionsofinterest,itshouldbeabletoconductelectronsfromtheactivesite,anditshouldbesufficientlyactivetocatalyzewateroxidationtooxygen.Furthermore,itshouldbecheap,easytohandleandpreferentiallynon-toxic.

Weexploretwodifferentoxideclasses:pristineanddopedperovskiteoxides(ABO3,whereAisthealkalineearthorlanthanidemetalandBthe1strowtransitionmetal)andseveralMnO2polymorphs.

Stabilityandtheelectronicconductivityofdopedmaterialsareassessedandcomparedtopristinecatalystsbycomputingformationenergiesandanalysingtheelectronicstructureofbulkcrystals,respectively.Afterselectingstabledopants,wecalculatetherelevantsurfaceterminationanddeducethereactionoverpotentialfromtheenergeticallymostfavourablereactionmechanism.

Fortheperovskiteoxides,weobserveaninversecorrelationbetweentheOERactivityandstabilitysuchthatthemostcatalyticallyactiveLaCrO3andCaFeO3oxidesarenotsufficientlystableandwillreadilydissolveunderoperatingconditions.We identify Fe4+, Co3+(IS),Ni3+ andMn3+/Mn4+ pairs as electronically conductive species and distinguishamongthreedifferentelectronconductiontypes:intrinsicconductance(Fe4+andNi3+),electronpolaronhopingalongthe Metal-Oxygen-Metal chains (Mn3+/Mn4+ and Cr3+/Cr2+) and conduction via oxygen holes in the valence band.Although,theintrinsicstabilitiesofLaperovskitesareratherlow,theyarelikelytobethemoststablecatalystsinopensystemsbecausetheydonotformcarbonates,which,otherwise,arereadilyformedwithalkalineearthmetals.FromacombinatorialanalysisonLaperovskites,weidentifyCudopedLaMnO3,MndopedLaCuO3andLaCoO3andNidopedLaCoO3asthemostpromisingoxygenevolvingcatalysts.WefindthattheoxygenevolutionactivityofMnO2polymorphsreducesintheαMnO2>βMnO2>γMnO2sequence.WechooseαMnO2asthemostactivecatalystandsubsequentlyinvestigatewhetheritsperformancecanbefurtheredbydoping.TheelectronicconductanceisgreatlyimprovedbycreatingMn3+sites,i.e.Mn3+/Mn4+pairs.Thiscanbeachievedbyintercalatingelectrolyteions(e.g.Na+orK+)inlargeαMnO2holesorintroducingoxygendefects/foreignatomsinthestructure.Fromthecatalyticanalysis,weidentifyPddopedαMnO2asthemostactivecatalystforoxygenevolution.

ThisworkwassupportedbytheHorizon2020framework,grantnumber646186.


177

AbstractNo.240

INSIDE–In-situDiagnosticsinWaterElectrolysers

IndroBiswasaandMathiasSchulzeaaDeutschesZentrumfürLuft-undRaumfahrte.V.(DLR),

InstitutfürTechnischeThermodynamik,Pfaffenwaldring38-40,70569Stuttgart,Germany

[email protected]

Summary.Anin-situtoolforonlinemonitoringofoperatingconditionsisdevelopedforPEMWE,AE,andAEMWE.

Abstract.InthisjointR&DprojectsupportedbytheEUFuelCellandHydrogenJointUndertaking,anelectrochemicalin-situdiagnosticstoolforthemonitoringoflocallyresolvedcurrentdensitiesinpolymerelectrolytemembranefuelcellsisadaptedtothreedifferentwaterelectrolysistechnologies:basedonprotonexchangemembranes(PEMWE),onanion exchange membranes (AEMWE), and alkaline water electrolysis (AE). The developed tools allow correlatingperformanceissuesandageingprocesseswithlocalanomalies.Thecorrespondingmechanismsareinvestigatedwithex-situanalytics.

INSIDEconsortium:– Deutsches Zentrum für Luft- und Raumfahrt e.V., Stuttgart, Germany (Coordination, polymer electrolytemembranebasedwaterelectrolysis)– NELHydrogenAS,Notodden,Norway(Alkalinewaterelectrolysis)– HeliocentrisItalyS.r.l.,Crespina,Italy(Anionexchangemembranebasedwaterelectrolysis)– CentreNationaldelaRechercheScientifique,France(Ex-situanalytics)– UniversitédeStrasbourg,Strasbourg,France(Ex-situanalytics)– HochschuleEsslingen,Esslingen,Germany(Ex-situanalytics)

Fig.1.1stprototypeforAEMWEhasbeenconstructed

Thepatentedsegmentedprintedcircuitboard(PCB)forthemonitoringofcurrentdensitydistributionsinPEMbasedfuelcellsisusedandcontinuouslyimprovedfore.g.theinvestigationofspecificmechanismsorsystematicoptimisation.

Theembeddingofanin-situdiagnosticstoolinwaterelectrolysissystemenables:–monitoringofperformanceandlocalanomaliesduringoperation–revealingsystematicaldeficienciesnotdetectablewithoff-linediagnostics–correlatingdegradationmechanismsandsystemparameters–identifyingandpreventingcriticaloperation–systematicallyimprovingtheefficiencyofwaterelectrolysis


178

AbstractNo.241

Innovativephotoelectrochemicalcellsbasedonpolymericmembraneelectrolytesandsuitableporousphotoanodes

T.Stoll,G.Zafeiropoulos,I.DoganH.Genuit,M.N.TsampasDutchInstituteForFundamentalEnergyResearch-DIFFER,

DeZaale20,5612AJ,Eindhoven,[email protected]

Summary.WehavedevelopedandevaluatedanovelphotoelectrochemicalcellwithpolymericelectrolytesinfluencedbythedesignofPEMelectrolysers,whichoperateswithcheapandabundantphotoanodematerials.ThisinnovativedesignallowsustoenablenoveloperationmodesforH2generationviawateroralcoholelectrolysis.

Abstract.Photoelectrochemical(PEC)splittingofwaterbythedirectuseofsunlightisanideal,renewablemethodofhydrogen production. The majority of PEC cell studies utilize aqueous solutions as both the electrolyte and thephotoanode reactants. Only few studies have attempted to separate the two half reactions compartments with apolymericelectrolytemembrane(PEM).Inmostofthesecasesacidicandalkalinesolutionsareusedasanodereactants,butlittleworkhasbeendonewithgaseousfeedstockfortheanode.Inourstudyweusedsolid-stateelectrolytesinconjunctionwithgaseousreactants inaPEM-PECcell.Suchsystemshowspotentialadvantagesovertheliquidonessuchasoperationathigher temperaturesandpressures (for improving theelectrodekinetics),directproductionofcompressedH2, compactandrobustdesignbesides theseparationof theproductsat theelectrodecompartments.Moreover,itallowsawater“neutral”operation,inwhichwateriscapturedfromthehumidityintheambientair.

Typically in PEM-PEC studies the powder photocatalyst is dispersed on the porosity of carbon supports (to ensureelectronic conductivity). This choice presents two main disadvantages: (i) the formation of many photogeneratedspeciesrecombinationpathwaysatthepowdergrainboundariesand(ii)poorstabilityafterprolongedoperation,sincethephotocatalyticpowdermaybecomeunbound to thesubstrate.Toovercomethese issues,wehavesuccessfullydemonstratedanalternativedesign forPEM-PECphotoelectrodes,whichutilizesaTi-webofmicrofibersas startingmaterial.ElectrochemicalanodizationofthissubstratehasledtothefabricationofTiO2nanotubesarrays.Inordertoenhancethescopeofapplicationofoursystemtothevisibledomainofsunlight,wechosetomodifyourTiO2electrodeswithlowerband-gapsemiconductors.IthasbeenshownintheliteraturethattheadditionofaWO3layeronTiO2leadstoanincreaseofthecurrentalongwitharedshiftedlightabsorption.FurthermoreitisalsowellknownthatWO3/BiVO4associationleadstosomeofthemostvisiblelightactivephotoanodes.Wehavedevelopedphotoanodeswhicharebasedon the double junction TiO2/WO3/BiVO4. Since theporous nature of the titanium substrate preventsthe use of conventional techniques such as spincoating, an alternative fabrication method wasdeveloped. The protocol involves sputtering ofW,followedbyanodizationandthenbysuccessiveioniclayer adsorption and reaction (SILAR) method forBiVO4deposition.Inthiswaywewereabletocreatethe desired double junction and the synergiesbetween the different layers were studied byphotoelectrochemistry. The performances of theTiO2/WO3 and TiO2/BiVO4 assemblies at pH=1remained quite limited with a maximumphotocurrent of 0.1 mA/cm2 at 1.2V. But the fullassociation TiO2/WO3/BiVO4 gave a significantmagnificationofthecurrenttoreach~1mA/cm2at1.2V(Figure1).

Figure1:EffectofBiVO4loadingonTiO2/WO3substrateundersimulated AM1.5 solar light at the chopped (On/Off) lightconditionatpH=1.


179

AbstractNo.242

ElectrolysersbasedonCsH2PO4toworkathighpressuresandmoderatetemperatures

LauraNavarretea,MateuszTaracha,Chung-YulYoobandJoséM.SerraaaInstitutodeTecnologíaQuímica(UniversitatPolitècnicadeValència–ConsejoSuperiordeInvestigaciones

Científicas),Av.LosNaranjos,s/n,46022Valencia,SpainbKoreaInstituteofEnergyResearch,152Gajeong-ro,Yuseong-gu,Daejeon,SouthKorea

[email protected]

Summary.ElectrolysersabletoworkathighpressuresandmoderatetemperatureweredevelopedusingCsH2PO4aselectrolyte base. The electrodes electrocatalytic activity was tailored by using different metals and electrodeconfigurations.StableproductionofhydrogenwasobtainedduringsteamelectrolysiswithhighFaradicefficiencies.

Abstract.CsH2PO4isanew-generationelectrolyteforfuelcellsthatenableoperationatintermediatetemperature(200- 300 ºC) [1]. CsH2PO4 transforms into cubic phase showing superprotonic conductivity when the temperature isincreasedabove230ºC[2].Unlikehightemperatureelectrochemicalcells,thelowoperationtemperatureofCsH2PO4allowsthepossibilitytousecheapmaterialsforthestackconstruction,reducingthecostofthedeviceandincreasingthelifetime.Moreover,duetothehigheroperationtemperature,comparedwithpolymericmembranefuelcells(80ºC),differentcatalystsinsteadofplatinumcanbeemployed,increasingthepossibilitiesofthecell.

Usually,thesamematerialcanbeusedaselectrolyteinafuelcellorelectrolysercell,butthereactionsinvolvedarethereverse. This premise was taken into account and CsH2PO4 was tested as electrolyte material in a fuel cell andelectrolysermode.

Different cell configurations were studied for the optimization of the cell performance. Firstly, symmetrical cellssupportedontheelectrolyteweremanufacturedbyemployingthesameelectrodematerialforcathodeandanode.CarbonGasDiffusionLayer(GDL)wasemployedaselectrodebackboneanddifferentcatalystsasCu,ZnandPtwereinfiltrated.Some improvementswereperformedas toenlarge the triplephaseboundaryandcompositeelectrodesweredesigned.CsH2PO4wasselectedasprotonphasewhereascarbonpowderimpregnatedwithdifferentmetalswasused as electronic conductor material. Secondly, the electrolyte thickness was reduced by supporting the cell ondifferentsupports:steelornickelporoussupports,reducingthethicknessoftheelectrolytefrom1.8mmto100µm.Furtherstudieswereperformedinordertoimprovethemechanicalstabilityofthesample.Theadditionofanepoxyintheelectrolyte[3]allowedworkingwithasystempressureof20bar.DifferentratiosofCsH2PO4andepoxywerestudiedinordertoobtaingoodconductivityandgoodmechanicalstability.

Furthermore,theinfluenceoftotalpressurewastestedforthedifferentcells,andresultsshowedthatincreasingthepressureinthesystem,theperformanceincreasedinmorethansixtimes.Theresultshighlightedthebiginfluenceofthesystempressureandoperationtemperature.Duringthetimethataconstantcurrentwasappliedtothesysteminthesteamelectrolysismode, thecompositionof theoutletstreamwasanalysedbyamassspectrometerandagaschromatograph.StableproductionofH2wasobservedandtheFaraday’sefficiencyachievedvaluesaround100%.

[1]S.M.Sossina,C.R.I.Chisholm,K.Sasaki,D.A.BoysenandU.Tetsuya,Faradaydiscussions,2007,134,17-39.

[2]D.A.BoysenandS.M.SossinaChem.Mater.2003,15,727-736.

[3]G.Qing,R.Kikuchi,A.Takagaki,T.Sugawara,S.T.Oyama,Electroc.Acta,2015,169,219-226

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