An Intermediate Temperature

Metal-Supported Proton-Conducting

Solid Oxide Fuel Cell Stack

17th Annual SOFC Workshop

July 19, 2016

Stack Concept

2

Feature Lead Organizations

Proton-Conducting

Oxide

Metal Support

Internal Fuel

Reforming

CH4, H2O CH4, H2O, CO2, CO

Air Air – O2 + H2O

Metal supported p-SOFC with internal CH4 reforming

CHP System Concept & Efficiency

3

Assumptions

Methane Conversion 90%

H2 Utilization 80%

OCV (V/Cell) 1.05

ASR (cm2) 1

Current Density (mA/cm2) 200

Parasitic Power / Stack Power 9%

Inverter Efficiency 95%

Heat Recovery Temp 75 °C

Overall stack

efficiency Net electric

efficiency

Effective

Electric

Efficiency

(57%)

12.8 g/s

35 C

13.4 g/s 0.6 g/s

80 C 35 C

13.4 g/s 12.6 g/s 12.7 g/s 12.7 g/s

246 C 463 C 538 C 385 C

12.6 g/s

15 C

0.6 g/s

463 C

0.7 g/s

13.4 g/s 463 C

598 C

12.7 g/s 0.2 g/s

385 C 15 C

HEX Hot In

Burn In Cath

Cath ExitCath In Boil Out

Anode Out

HEX Hot Out

NG In

Rec. H2O

Steam

HR Exit

Exhaust

Air Inflow Cathode

SR & Anode

PC SOFC Stack

Stack Afterburner

Exhaust Heat RecoveryHeat Exchanger

Fresh Fuel & SteamMixer

Building/Potable Water Heating/Cooling Sub-System

Natural Gas

Exhaust

SystemBlower

Recuperator

Air CooledExhaust

Condenser

Boiler

Recovered Water Pump

PCO-Electrolytes: Exceed Target Conductivity

4

1.0 1.5 2.0 2.5 3.010

-6

10-5

10-4

10-3

10-2

1000/T (K-1)

Co

nd

uctivity (

S/c

m)

comp 1 1.91

comp 2 1.78

comp 3 1.66

comp 4 2.00

target 1.5

, 10-2S/cm

700600 500 400 300 200 100

Temperature (oC)

pH2O = 0.031 atm

Balance N2

Gen-2

20 25 30 35 40

Inte

nsity (

a.

u.)

2 Theta

20 40 60 80

after 100% CO2 500

oC/12h

Inte

nsity (

a.

u.)

2 Theta

as-sintered

CO2 stability of Gen-2 Electrolyte

5

BaCO3 BaCO3

0 300 600 900

99

102

105

108

N2

40% CO2 & N

2

Mass (

%)

Time (min.)

N2

0

200

400

600

800

1000

Tem

pera

ture

(oC

)

• No carbonate detected by diffraction

• No weight gain under flowing CO2

800 °C

dehydration

Overall Cell Performance on H2

6

0.0 0.5 1.0 1.5 2.0 2.5 3.00.0

0.2

0.4

0.6

0.8

1.0

1.2 700 C

650 C

600 C

550 C

500 C

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Po

we

r De

nsity

(w c

m-2)

0.0 0.4 0.8 1.2 1.6 2.00.0

0.2

0.4

0.6

0.8

1.0

700

650

600

550

500

Zreal [ cm2]

-Z im

ag

[c

m2]

OCV (V) Ohmic ( cm2)

(electrolyte)

Non-ohmic ( cm2)

(anode + cathode)

Total resistance

( cm2)

Maximum power

density (W cm-2)

600 1.080 0.342 0.285 0.632 0.409

550 1.105 0.418 0.682 1.112 0.280

500 1.126 0.561 2.697 3.277 0.154

Anode

Electrolyte

Cathode

Cell Performance Stability Evaluation @ 500 C

7

0 20 40 60 80 1000.0

0.1

0.2

0.3

0.4

0.5

Curr

ent

Den

sity (

A c

m-2

)

Time (h)

@ 0.7 V

humidified H2 / cell / air

T = 500 °C

0.0 0.5 1.00.0

0.2

0.4

0.6

0.8

1.0

1.2

Initial

After 100hs

Current Density (A cm-2)

Volta

ge

(V

)

0.0

0.2

0.4

Pow

er D

ensity

(w c

m-2)

0 1 2 30.0

1.5

Initial

After 100hs

Zreal [ cm2]

-Z im

ag

[c

m2]

Combinatorial Electrode Development

8

Pr concentration

Cathode: BaZrYO3 - BaPrYO3

Typical spectra

Pr-rich, fixed composition

Vary diameter

Observation: strong composition dependence, slight diameter dependence

diameter

BYZ BYP

Fuel Processing

9

Internal CH4 steam reforming

Strategy

Dev. Approach

Achieved at W/F<3 kg/(mol/s)CH4

Fuel Processing Test: o-SOFC Cell @ 600 °C

10

0

200

400

600

800

1,000

1,200

0 50 100 150

Vo

ltag

e (

mV

)

Current Density (mA/cm2)

CH4

H2

Linear (CH4)

Linear (H2)

Experimental Performance

Metric & Target

PM=52%

Subject to the EAR: ECCN EAR99

Fuel Processing

11

Internal CH4 steam reforming

Strategy

Dev. Approach

PM=52%

Metal Support Design

12

Metal Porous Sheet (substrate for p-SOFC trilayer)

Metal C-Ring Inserts/Orifices (3 out of 4 visible)

Metal Foam (substrate for reforming catalyst)

Metal Stamped Dish

Insulator Couplings (2 out of 4 visible)

(1)

(2)

(3)

(4)

(5)

Subject to the export

restrictions on the title page..

Enabling Fabrication Approach: Reactive Spray Deposition Technology (RSDT)

Cell Manufacturing Process: RSDT

Flame-based deposition process

Direct deposition of trilayer cell

onto metal support

Elimination of sintering steps

13

RSDT Deposition Targets

14

Porous metal support

Gen 1 Half Cell by RSDT Process

Achieved dense electrolyte

15

FIB cross section performed using FEI Helios G3

RSDT Full Cell Deposition

16

Anode Anode-Electrolyte Anode-Electrolyte-Cathode

Electrolyte on anode

no electric shorts

Summary

Progress

Cell materials

Internal fuel processing

Stack design

RSDT fabrication process

Next Steps (Major upcoming milestones)

Fuel cell fabrication by RSDT and performance verification

100 W Stack fabrication and testing

17

Acknowledgements

18

Organization Team Members

Sossina Haile, Sihyuk Choi, Chris

Kucharczyk, Daekwang Lim

John Yamanis

Radenka Maric, Tim Myles, Ryan Ouimet

Ichiro Takeuchi, Xiaohang Zhang, Yangang

Liang

Tianli Zhu, David Tew, Justin Hawkes

Grigorii Soloveichik, Scott Litzelman, John Tuttle,

John Lemmon

The information, data, or work presented herein was funded in part by the Advanced Research Projects

Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000498.

Back Up

19

Proton Conducting Oxide

20

High-Throughput Material Evaluation Approach

RSDT Anode Microstructure Refinement

30 wt% Nafion : NiO

Porosity: 26%

7.5 wt% Nafion : NiO

Porosity: 10% 0 wt% Nafion : NiO

Porosity: 1%

Decreasing Binder Concentration

Decreasing Porosity

Effect of Binder on Porosity and Microstructure

20 μm 20 μm 20 μm

Porosity based on stereology, MIP in progress

M4.2.1.1 RSDT Anode Microstructure Refinement

22

Deposited electrolytes onto 0%

and 7.5% anodes and performed

resistance check

Check performed with

Agilent 43388 milliohmmeter

Stack gold plate/carbon fiber

mat/sample/carbon fiber mat

(6 cm2) /gold plate

0% binder 7.5% binder Sample Resistivity

(Ω-cm)

Base 1

Doctor bladed

SS430

300

Anode (30 wt%

Nafion)

144000

Half cell >108

Half Cell

System Concept

23

12.8 g/s

35 C

13.4 g/s 0.6 g/s

80 C 35 C

13.4 g/s 12.6 g/s 12.7 g/s 12.7 g/s

246 C 463 C 538 C 385 C

12.6 g/s

15 C

0.6 g/s

463 C

0.7 g/s

13.4 g/s 463 C

598 C

12.7 g/s 0.2 g/s

385 C 15 C

HEX Hot In

Burn In Cath

Cath ExitCath In Boil Out

Anode Out

HEX Hot Out

NG In

Rec. H2O

Steam

HR Exit

Exhaust

Air Inflow Cathode

SR & Anode

PC SOFC Stack

Stack Afterburner

Exhaust Heat RecoveryHeat Exchanger

Fresh Fuel & SteamMixer

Building/Potable Water Heating/Cooling Sub-System

Natural Gas

Exhaust

SystemBlower

Recuperator

Air CooledExhaust

Condenser

Boiler

Recovered Water Pump

Net DC Power (W)= 5000

Net AC Power / Methane LHV= 51%

Recovered Heat /Methane LHV= 25%

Effective Electric Efficiency= 57%

Performance Summary5 kW Residential CHP System