research article synthesis and characterization of...

Hindawi Publishing CorporationISRN NanotechnologyVolume 2013 Article ID 653237 5 pageshttpdxdoiorg1011552013653237

Research ArticleSynthesis and Characterization of Electrophoretically DepositedNanostructured LiCoPO4 for Rechargeable Lithium Ion Batteries

S Priya Nair U Jyothsna P Praveen A Balakrishnan K R V SubramanianShantikumar V Nair and N Sivakumar

Nanosolar Division Amrita Centre for Nanosciences and Molecular Medicine Amrita Vishwa Vidyapeetham Kochi 682 041 India

Correspondence should be addressed to Shantikumar V Nair shanthinairgmailcom and N Sivakumar nskdnpgmailcom

Received 24 May 2013 Accepted 10 August 2013

Academic Editors B Coasne C-L Hsu A Hu D K Sarker and D K Yi

Copyright copy 2013 S Priya Nair et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Nanosized LiCoPO4(LCP) was prepared using a simple sol-gel method For the first time electrophoretic deposition process was

employed to fabricate a LiCoPO4cathodematerial in order to improve the electrochemical performanceThe prepared powder was

deposited on titanium plate by electrophoretic deposition and their electrochemical properties were studied The electrochemicalproperties were analyzed by using cyclic voltagramm studies impedance studies and chargedischarge tests The thickness of theprepared cathode material was found to be 11-12120583m by using scanning electron microscope The initial specific capacity and thecharge transfer resistance (Rct) of the prepared cathodewas 103mAhg and 851Ω respectivelyThe chargedischarge profiles showedmoderate columbic efficiency of 70

1 Introduction

Lithium-ion batteries exhibit good electrochemical perfor-mance compared to other types of batteries due to longstorage life and environmentally friendly and low main-tenance They are the focus of attention as good energystorage devices and are nowadays commonly used in portableelectronic devices such as laptops mobile phones cameraand so forth For better performance cathode materials withhigh specific energy density high power density and excel-lent thermal stability are necessary for lithium-ion batteries[1 2]

LiCoO2is the commonly used cathode material It has

both high voltage and capacity but has its own disadvantageslike high cost toxic properties and safety issues [3 4] So aquest for other cathode materials arises Cathode materialshaving the general formula LiMPO

4(M = Fe Co Mn

and Ni) are seeking attention nowadays [5ndash9] They arehaving high theoretical capacity approximately 170mAhgTheir operating voltages are high They are having a stablestructure on charging and discharging thermal stability andflat voltage profile [10 11]

Lithium cobalt phosphate (LiCoPO4) has high energy

density (750Wh)which is comparable to lithium cobalt oxide(LiCoO

2) [12] LiCoPO

4is one material which has high

voltage and capacity compared to LiCoO2and is predicted

to have sim16 times the specific energy of LiCoO2[13ndash16] It

can operate at high voltage typically 5V It is cost effectiveand one of the promising cathode material But their maindisadvantages are their poor electronic and ionic conductivityand poor rate cyclability [17 18] Even though the theoreticalcapacity of LiCoPO

4is 167mAhg the obtained values are

still lower due to the above reason Reduction in particle sizeto nanometer size doping with some metal ions and addingcarbon coating are the method to overcome these problems[19] If we are able to overcome the low electronic and ionicconductivity of LCP it would be the best alternative cathodematerial

In the present work LiCoPO4powders were synthesized

using simple sol-gel method The synthesized powders weresuccessfully deposited on titanium plate electrophoreticallywhich is reported for the first time The work includesthe study of electrochemical behavior of electrophoreticallydeposited LiCoPO

4cathode materials and to see how this

2 ISRN Nanotechnology

20 30 40 50 602120579

Inte

nsity

(au

)

(020

)

(011

)(1

20)

(101

)

(200

)

(031

)

(131

)(2

11)

(140

) (221

)

(111

)

(112

)

(202

)(3

11)

(222

)

(142

)(1

60)

(331

)(3

40)(020

)

(011

)(1

20)

(101

)

(200

)

(031

)

(131

)(2

11)

(140

) (221

)

(111

)

(112

)

(202

)(3

11)

(222

)

(142

)(1

60)

(331

)(3

40)

Figure 1 XRD pattern of LiCoPO4

method of deposition has its influence on the properties likespecific capacity impedance chargedischarge profiles andcycle stability

2 Experimental Details

Lithium acetate cobalt acetate and orthophosphoric acidwere used as starting materials and dissolved in 30mL30mL and 40mL of acetone respectively Then the threesolutions were mixed thoroughly and kept at 80∘C until thegel formation Then the gel was kept for overnight drying inthe oven in order to get the powder material After dryingthe gel completely resultant powder was crushed well in theagate mortar Then the powder was kept for presintering at400∘C for 5 h under air followed by sintering at 750∘C for 24 hunder air to get the crystalline phase The resultant productwas ground well to get the single phase olivine LiCoPO

4

(LCP)Electrophoretic deposition of LCP was done by taking

platinum rod (inert electrode) as the anode and titaniumplate as the (substrate) cathodeThe solution was prepared bytaking isopropanol as the solvent 30mg of LCP was added to15mL of isopropanolThe solution was sonicated for 30 min-utes to get the powder well dispersed in the solvent 2mg oflithium chloride was added to charge the solution The mix-ture was then stirred for 15minutes EPD process was done bygiving a voltage of 60V for 30 minutes to yield thin coatingof LCP on titanium plate followed by annealing at 70∘C for10 hrs

XRD patterns were obtained by XRD Xrsquopert PRO ana-lytical with Cu ka The morphology of sample was studiedby scanning electron microscope (SEM model JEOL JSM6490LA) XPS (Kratos analytical Shimadzu) was used tostudy the oxidation state and to see whether LCP has coatedinto titanium plateThe roughness of the samples was studiedby Profilometer (Veeco Dektak 150) AUTOLAB (electro-chemical workstation NewportModel) was used to study theelectrochemical properties The electrochemical properties

like cyclic voltagramm and impedance were studied usinga three-electrode system the calomel electrode as referenceelectrode platinum as counter electrode and the LCP coatedtitanium plate as working electrode The charge dischargeprofiles were studied by using two-electrode systems Theplatinum rod was used as counter electrode and workingelectrode was the same as that for CV and impedance studyThe electrolyte was 20mL of propylene carbonate to which212 g of lithium perchlorate was added

3 Results and Discussion

31 Phase Analysis TheX-ray diffraction pattern of pure LCPis shown in Figure 1 The XRD pattern of pure LCP clearlyshows the formation of single phase olivine Lithium cobaltphosphate (LCP) with an orthorhombic structure with spacegroup Pnma (JCPDS file number 32-552) [20] The averagegrain size is 35 nm which was calculated from the Scherrerrsquosformula

32 Scanning Electron Microscopy SEM image of pure LCPis shown in Figure 2(a) From the figure we can clearlysee that the particles are distributed in flake like structurenonuniformlyThe average particle sizewas found to be about200 nm Figure 2(b) shows the SEM image of electrophoret-ically deposited LCP on titanium plate The nanosized parti-cles were found to get agglomerated to minimize the surfaceenergy The cross section of the deposited film is shown inFigure 2(c) The thickness of the film was found to be 11-12 120583m

33 XPS Studies Figure 3 shows the XPS spectrum of LCP[21] As seen from the graph the binding energy of lithiumwas58 eV The binding energy of phosphorus was 137 eV whichwas closed to the characteristic binding energy of phospho-rus As for oxygen the binding energywas found to be close to535 which was in good agreement with the standard bindingenergy In the case of cobalt the binding energy was foundto be close to 785 But the high resolution spectrum (givenin the inset) shows two distinct peaks which correspond totwo different oxidation states Co2p

32which was located

at 78461 eV and Co2p12

which was located at 80066 eVwhich was in close agreement with the characteristic bindingenergies

34 Electrochemical Measurements The CV curves of pureLCP are shown in Figure 4 The selected potential windowcut-off was from minus5 to 3V with the scan rate of 01 VS Theoxidation and reduction peaks are located at minus2152V andminus2628V respectivelyThe oxidation peak corresponds to thepoint at which lithium was extracted from LCP structure andreduction peak corresponds to the point at which lithiumwas reinserted into the LCP crystal structurethe specificcapacity of the pure LCP cathode material was calculated tobe 103mAhg Specific capacity versus cycle number studyis given in Figure 5 The specific capacity was 103mAhgin the first cycle After that the value decreases and wascomparatively stable from the 4th cycle to the 15th cycle

ISRN Nanotechnology 3

(a) (b) (c)

Figure 2 SEM image of (a) lithium cobalt phosphate powder (b) electrophoretically deposited lithium cobalt phosphate film and (c) crosssection of deposited film

Li P Cl

Co

O

Binding energy

Binding energy

Inte

nsity

Inte

nsity

800600400200

50000

40000

30000

20000

0

10000

17000165001600015500150001450014000

775 780 785 790 795 800 805

Co2p32 Co2p12

Figure 3 XPS spectra of lithium cobalt phosphate powder (Insetshows the high resolution spectrum of Cobalt)

420minus2minus4minus6

minus0016

minus0014

minus0012

minus0010

minus0008

minus0006

minus0004

minus0002

0000

0002

0004

Curr

ent (

A)

minus2152

minus2682

Voltage (V)

Figure 4 CV curve of LiCoPO4

110

100

90

80

70

60

50

40

30

20

10

0

Spec

ific c

apac

ity

0 5 10 15 20 25Cycle number

Figure 5 Graph showing specific capacity versus cycle number ofLCP cathode material

(45mAhg to 43mAhg) The system has comparable initialperformance but it reduces and becomes stable at the fourthcycle The lithium extraction takes place at a large rate atthe beginning then the insertion was not happening at anequivalent rate which may result in a diminished value afterthe 4th cycle

Figure 6 shows the impedance spectra of LCP and thefrequency range given for impedance measurements werefrom 100 kHz to 1mHz For pure LCP the curve consistsof a depressed semicircle which does not touch the 119909-axisfollowed by a line which indicates Wardburg resistance [2223] Some scatterings were observed in the low frequencyrange The value of charge transfer resistance from thecurve is 851Ω which was fairly better compared to mostof the other reported values Lithium cobalt phosphate hashigh impedance generally Techniques like carbon coatingwere done to minimize the impedance and to improve theconductivity But here the formation of a thin layer composedof nanosized particle itself reduces the impedance to lowervalues The columbic efficiency for the first cycle was found


600

400

200

00

1000

Z998400(Ohm)

minusZ998400998400

(Ohm

)

Figure 6 Impedance spectra of LCP cathode material

Cycle number

100

90

80

70

60

50

40

30

20

10

00 2 4 6 8 10

Col

umbi

c effi

cien

cy

Figure 7 Columbic efficiency versus cycle number for LCP cathodematerial

to be 70 in Figure 7 Columbic efficiency of the 3rd 5th7th 9th and 10th cycle are 65 61 57 55 and 53respectively

4 Conclusion

LiCoPO4powder was successfully developed by a simple sol-

gel method The XRD results showed pure orthorhombicstructure without any impurity The grain size was found tobe 35 nm SEM image showed flake like structures havingan approximate particle size of 200 nm The SEM imageof LiCoPO

4deposited titanium plate showed agglomerated

particles LiCoPO4was successfully deposited onto to the

titanium plate for the first time by applying a voltage of 60Vfor 45 minutes Using XPS spectra the presence of LiCoPO

4

onto titanium plate was confirmed but a minor quantityof lithium chloride was also deposited The thickness of

the LCP coating was found to be 11 120583mThe cyclic voltametrystudy showed that pure LCP was having a discharge capacityof 103Ahg The 119877ct value of pure LCP was found to be851Ω The chargedischarge mechanism of LCP was foundto be comparatively stable for LCP LCP has moderateelectrochemical performance initially but it sustains theperformance throughout the next cycles Electrophoreticdeposition results in uniform LCP coating which is a novelmethod of cathode fabrication since the electrochemicalperformance is comparable with the previous results

Acknowledgment

Ministry of New Renewable Energy Government of Indiais gratefully acknowledged for a Centre Grant to AmritaCentre for Nanosciences Amrita Vishwa Vidyapeetham forthis work

References

[1] M Prabu S Selvasekarapandian A R Kulkarni SKarthikeyan G Hirankumar and C Sanjeeviraja ldquoIonictransport properties of LiCoPO

4cathode materialrdquo Solid State

Sciences vol 13 no 9 pp 1714ndash1718 2011[2] D-W Han Y-M Kang R-Z Yin M-S Song and H-S Kwon

ldquoEffects of Fe doping on the electrochemical performanceof LiCoPO

4C composites for high power-density cathode

materialsrdquo Electrochemistry Communications vol 11 no 1 pp137ndash140 2009

[3] C Chang J Xiang X Shi X Han L Yuan and J SunldquoHydrothermal synthesis of carbon-coated lithium vanadiumphosphaterdquo Electrochimica Acta vol 54 no 2 pp 623ndash6272008

[4] B Zhang J-Q Liu Q Zhang and Y-H Li ldquoElectrochemicalperformance of Al-substituted Li

3V2(PO4)3cathode materials

synthesized by sol-gel methodrdquo Transactions of NonferrousMetals Society of China vol 20 no 4 pp 619ndash623 2010

[5] N N Bramnik K G Bramnik C Baehtz and H EhrenbergldquoStudy of the effect of different synthesis routes on Li extraction-insertion from LiCoPO

4rdquo Journal of Power Sources vol 145 no

1 pp 74ndash81 2005[6] A K Padhi K S Nanjundaswamy and J B Goodenough

ldquoPhospho-olivines as positive-electrode materials for recharge-able lithium batteriesrdquo Journal of the Electrochemical Societyvol 144 no 4 pp 1188ndash1194 1997

[7] O Garcıa-Moreno M Alvarez-Vega F Garcıa-Alvarado et alldquoInfluence of the structure on the electrochemical performanceof lithium transition metal phosphates as cathodic materialsin rechargeable lithium batteries a new high-pressure form ofLiMPO

4(M = Fe and Ni)rdquo Chemistry of Materials vol 13 no 5

pp 1570ndash1576 2001[8] A Yamada M Hosoya S-C Chung et al ldquoOlivine-type cath-

odes achievements and problemsrdquo Journal of Power Sourcesvol 119ndash121 pp 232ndash238 2003

[9] Y Wang and G Cao ldquoDevelopments in nanostructured cath-ode materials for high-performance lithium-ion batteriesrdquoAdvanced Materials vol 20 no 12 pp 2251ndash2269 2008

[10] E Markevich R Sharabi H Gottlieb et al ldquoReasons forcapacity fading of LiCoPO

4cathodes in LiPF

6containing

electrolyte solutionsrdquo Electrochemistry Communications vol 15no 1 pp 22ndash25 2012


[11] J Wolfenstine ldquoElectrical conductivity of doped LiCoPO4rdquo

Journal of Power Sources vol 158 no 2 pp 1431ndash1435 2006[12] D-W Han Y-M Kang R-Z Yin M-S Song and H-S Kwon




[13] J Wolfenstine J Read and J L Allen ldquoEffect of carbon onthe electronic conductivity and discharge capacity LiCoPO

4rdquo

Journal of Power Sources vol 163 no 2 pp 1070ndash1073 2007[14] P Deniard A M Dulac X Rocquefelte et al ldquoHigh potential

positive materials for lithium-ion batteries transition metalphosphatesrdquo Journal of Physics and Chemistry of Solids vol 65no 2-3 pp 229ndash233 2004

[15] S Okada S Sawa M Egashira et al ldquoCathode propertiesof phospho-olivine LiMPO

4for lithium secondary batteriesrdquo

Journal of Power Sources vol 97-98 pp 430ndash432 2001[16] JWolfenstine U Lee B Poese and J L Allen ldquoEffect of oxygen

partial pressure on the discharge capacity of LiCoPO4rdquo Journal

of Power Sources vol 144 no 1 pp 226ndash230 2005[17] M E Rabanal M C Gutierrez F Garcia-Alvarado E C

Gonzalo andM E Arroyo-de Dompablo ldquoImproved electrodecharacteristics of olivine-LiCoPO

4processed by high energy

millingrdquo Journal of Power Sources vol 160 no 1 pp 523ndash5282006

[18] M Minakshi P Singh N Sharma M Blackford and MIonescu ldquoLithium extraction-insertion frominto liCoPO

4

in aqueous batteriesrdquo Industrial and Engineering ChemistryResearch vol 50 no 4 pp 1899ndash1905 2011

[19] P N Poovizhi and S Selladurai ldquoStudy of pristine and carbon-coated LiCoPO

4olivine material synthesized by modified sol-

gel methodrdquo Ionics vol 17 no 1 pp 13ndash19 2011[20] X Huang J Ma P Wu et al ldquoHydrothermal synthesis of

LiCoPO4cathode materials for rechargeable lithium ion batter-

iesrdquoMaterials Letters vol 59 no 5 pp 578ndash582 2005[21] L Tan Z Luo H Liu and Y Yu ldquoSynthesis of novel

high-voltage cathode material LiCoPO4via rheological phase

methodrdquo Journal of Alloys and Compounds vol 502 no 2 pp407ndash410 2010

[22] M Prabhu S Selvaraghavapandian M V Reddy and B V RChowdari ldquoImpedance studies on the 5-V cathode materialLiCoPO

4rdquo Journal of Solid State Electrochemistry vol 16 no 5

pp 1833ndash1839 2012[23] B Jin H-B Gu and K-W Kim ldquoEffect of different conductive

additives on chargedischarge properties of LiCoPO4Li batter-

iesrdquo Journal of Solid State Electrochemistry vol 12 no 2 pp 105ndash111 2008

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


20 30 40 50 602120579

Inte

nsity

(au

)

(020

)

(011

)(1

20)

(101

)

(200

)

(031

)

(131

)(2

11)

(140

) (221

)

(111

)

(112

)

(202

)(3

11)

(222

)

(142

)(1

60)

(331

)(3

40)(020

)

(011

)(1

20)

(101

)

(200

)

(031

)

(131

)(2

11)

(140

) (221

)

(111

)

(112

)

(202

)(3

11)

(222

)

(142

)(1

60)

(331

)(3

40)

Figure 1 XRD pattern of LiCoPO4

method of deposition has its influence on the properties likespecific capacity impedance chargedischarge profiles andcycle stability

2 Experimental Details

Lithium acetate cobalt acetate and orthophosphoric acidwere used as starting materials and dissolved in 30mL30mL and 40mL of acetone respectively Then the threesolutions were mixed thoroughly and kept at 80∘C until thegel formation Then the gel was kept for overnight drying inthe oven in order to get the powder material After dryingthe gel completely resultant powder was crushed well in theagate mortar Then the powder was kept for presintering at400∘C for 5 h under air followed by sintering at 750∘C for 24 hunder air to get the crystalline phase The resultant productwas ground well to get the single phase olivine LiCoPO

4

(LCP)Electrophoretic deposition of LCP was done by taking

platinum rod (inert electrode) as the anode and titaniumplate as the (substrate) cathodeThe solution was prepared bytaking isopropanol as the solvent 30mg of LCP was added to15mL of isopropanolThe solution was sonicated for 30 min-utes to get the powder well dispersed in the solvent 2mg oflithium chloride was added to charge the solution The mix-ture was then stirred for 15minutes EPD process was done bygiving a voltage of 60V for 30 minutes to yield thin coatingof LCP on titanium plate followed by annealing at 70∘C for10 hrs

XRD patterns were obtained by XRD Xrsquopert PRO ana-lytical with Cu ka The morphology of sample was studiedby scanning electron microscope (SEM model JEOL JSM6490LA) XPS (Kratos analytical Shimadzu) was used tostudy the oxidation state and to see whether LCP has coatedinto titanium plateThe roughness of the samples was studiedby Profilometer (Veeco Dektak 150) AUTOLAB (electro-chemical workstation NewportModel) was used to study theelectrochemical properties The electrochemical properties

like cyclic voltagramm and impedance were studied usinga three-electrode system the calomel electrode as referenceelectrode platinum as counter electrode and the LCP coatedtitanium plate as working electrode The charge dischargeprofiles were studied by using two-electrode systems Theplatinum rod was used as counter electrode and workingelectrode was the same as that for CV and impedance studyThe electrolyte was 20mL of propylene carbonate to which212 g of lithium perchlorate was added

3 Results and Discussion

31 Phase Analysis TheX-ray diffraction pattern of pure LCPis shown in Figure 1 The XRD pattern of pure LCP clearlyshows the formation of single phase olivine Lithium cobaltphosphate (LCP) with an orthorhombic structure with spacegroup Pnma (JCPDS file number 32-552) [20] The averagegrain size is 35 nm which was calculated from the Scherrerrsquosformula

32 Scanning Electron Microscopy SEM image of pure LCPis shown in Figure 2(a) From the figure we can clearlysee that the particles are distributed in flake like structurenonuniformlyThe average particle sizewas found to be about200 nm Figure 2(b) shows the SEM image of electrophoret-ically deposited LCP on titanium plate The nanosized parti-cles were found to get agglomerated to minimize the surfaceenergy The cross section of the deposited film is shown inFigure 2(c) The thickness of the film was found to be 11-12 120583m

33 XPS Studies Figure 3 shows the XPS spectrum of LCP[21] As seen from the graph the binding energy of lithiumwas58 eV The binding energy of phosphorus was 137 eV whichwas closed to the characteristic binding energy of phospho-rus As for oxygen the binding energywas found to be close to535 which was in good agreement with the standard bindingenergy In the case of cobalt the binding energy was foundto be close to 785 But the high resolution spectrum (givenin the inset) shows two distinct peaks which correspond totwo different oxidation states Co2p

32which was located

at 78461 eV and Co2p12

which was located at 80066 eVwhich was in close agreement with the characteristic bindingenergies

34 Electrochemical Measurements The CV curves of pureLCP are shown in Figure 4 The selected potential windowcut-off was from minus5 to 3V with the scan rate of 01 VS Theoxidation and reduction peaks are located at minus2152V andminus2628V respectivelyThe oxidation peak corresponds to thepoint at which lithium was extracted from LCP structure andreduction peak corresponds to the point at which lithiumwas reinserted into the LCP crystal structurethe specificcapacity of the pure LCP cathode material was calculated tobe 103mAhg Specific capacity versus cycle number studyis given in Figure 5 The specific capacity was 103mAhgin the first cycle After that the value decreases and wascomparatively stable from the 4th cycle to the 15th cycle


(a) (b) (c)


Li P Cl

Co

O

Binding energy

Binding energy

Inte

nsity

Inte

nsity

800600400200

50000

40000

30000

20000

0

10000

17000165001600015500150001450014000

775 780 785 790 795 800 805

Co2p32 Co2p12



minus0016

minus0014

minus0012

minus0010

minus0008

minus0006

minus0004

minus0002

0000

0002

0004

Curr

ent (

A)

minus2152

minus2682

Voltage (V)


110

100

90

80

70

60

50

40

30

20

10

0

Spec

ific c

apac

ity






600

400

200

00

1000

Z998400(Ohm)

minusZ998400998400

(Ohm

)


Cycle number

100

90

80

70

60

50

40

30

20

10

00 2 4 6 8 10

Col

umbi

c effi

cien

cy



4 Conclusion






4



Acknowledgment


References





















4cathodes in LiPF

6containing









4rdquo












4





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b) (c)


Li P Cl

Co

O

Binding energy

Binding energy

Inte

nsity

Inte

nsity

800600400200

50000

40000

30000

20000

0

10000

17000165001600015500150001450014000

775 780 785 790 795 800 805

Co2p32 Co2p12



minus0016

minus0014

minus0012

minus0010

minus0008

minus0006

minus0004

minus0002

0000

0002

0004

Curr

ent (

A)

minus2152

minus2682

Voltage (V)


110

100

90

80

70

60

50

40

30

20

10

0

Spec

ific c

apac

ity






600

400

200

00

1000

Z998400(Ohm)

minusZ998400998400

(Ohm

)


Cycle number

100

90

80

70

60

50

40

30

20

10

00 2 4 6 8 10

Col

umbi

c effi

cien

cy



4 Conclusion






4



Acknowledgment


References





















4cathodes in LiPF

6containing









4rdquo












4





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




600

400

200

00

1000

Z998400(Ohm)

minusZ998400998400

(Ohm

)


Cycle number

100

90

80

70

60

50

40

30

20

10

00 2 4 6 8 10

Col

umbi

c effi

cien

cy



4 Conclusion






4



Acknowledgment


References





















4cathodes in LiPF

6containing









4rdquo












4





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










4rdquo












4





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article synthesis and characterization of...

Documents