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Receiveddate:1998-10-21:1999-07-10:(1962),(),,,Biography:WANGXian-you(bornin1962),male,professor,postdoctor.·综述·王先友1, 朱启安1, 张允什2, 袁华堂2, 阎 杰2, 宋德瑛2(1.,411105;2.,300071):/,,(CPR)(AC)(PSCA)(GITT),,,CPRCITTPSCA;AC,ACWarburg:;;:TM912.9:A:1002-087X(1999)06-0335-04Measurementofchemicaldiffusioncoefficientoflithium-ionincathodeandanodematerialsofLi-ionbatteriesWANGXian-you1,ZHUQi-an1,ZHANGYun-shi2,YUANHua-tang2,YANJie2,SONGDe-ying2(1.CollegeofChemistryandChemicalEngineering,XiangtanUniversity,XiangtanHunan411105,China;2.InstituteofNewEnergyMaterialChemistry,NankaiUniversity,Tianjin300071,China)Abstract:Theprincipalelectrodereactionduringcharge/dischargeprocessforLi-ionbatteriesisintercala-tionandde-intercalationoflithiumionin/fromcathodeoranodematerials.Thus,thechemicaldiffusioncoefficientofLi-ionatcathodeoranodematerialsisanimportantparameter.Electrochemicalmethodsformeasuringthechemicaldiffusioncoefficientoflithium(DLi),e.g.,thecurrentpulserelaxationmethod(CPR),theelectrochemicalimpedancespectroscopymethod(AC),thepotentialstepchronoamperomtrymethod(PSCA)andthegalvanostaticintermittenttitrationtechnique(GITT)werereviewed.Evaluation,comparisonanddiscussionoftheelectrochemicalmethodsintermsoftheexperimentalresultsandpromo-tingR&DofLi-ionbatterieswereputemphasison.Accordingtotheanalysisanddiscussionabove,theCPR,GITTandPSCAmethodscanbeusedtodeterminethediffusioncoefficientefficientlywhendiffusionworksascontrollingratestepoftheelectrodereaction.ThoughACmethodcaneasilydistiguishthecon-trollingratestepofelectrodereaction,itcanonlybeusedtodeterminethediffusioncoefficientwhenimpedanceplothasWarburgimpedance.Keywords:Li-ionbatteries;diffusioncoefficient;electrochemicalmethod,,,LiNiO2LiCoO2LiMnO4,(GIC),Li-GIC;Li-GIC,[1]/,,,Fick,,335236199912ChineseJournalofPowerSources,(CPR)[2],(GITT)[3],(AC)[4](PSCA)[5],OCV(opencircuitvoltage)-,,,,,,,11.1(CPR)BasuWorrel[7],,[3,5,6,8]CPR,,,:U=f(t-1/2)(1):$U=VmdUdxISFAPDLit-12(2)Fick,(tnl2/DLi),:DLi=ISVmAFP12dUdxdUdt-12(3)I,AS,sVm,cm3/molA,cm2Ft,sl12dU/dx-dU/dt12(dU$U)-t-121CPR$Ut-12Fig.1Typicalexampleofthe$Uvs.t-12plotinCPRmethod,,,(2),dU/dt-12(1)1CPR$Ut-12,,(3)DLi1,Uchina[3,6],x=0,DLi10-9.5cm2/s,x,DLi1.2(AC)R0CDL/RCTZWWarburg(3)2Fig.2Simpleequivalentdiagramofelectrodeimpedance,(NyquistBody)23Nyquist,,,War-burg:Zw=RX-12-jRX-12(4)RWarburgX,3NyquistFig.3NyquistplotinFig.2j=-1(4),Warburg45m2DLi/l2,War-burg:R=-[Vm(2FA)](dU/dx)(I/DLi12)(5)l,VmFAdU/dx(3)Warburg,4Li1+xLaNb2O7x=0.74Fig.4CompleximpedancediagramofLi1+xLaNb2O7electrodeatx=0.74-dU/dx,DLi4Li1+xLaNb2O7x=0.74,WarburgDLi(6)2.3(GITT),,,5$UtI0S,$UsI0I0,S,,,Fick5CLi(x,t)/5t=DLi52CLi(x,t)/5x2(6)336:Vol.23No.6Dec.1999CLi(x,t=0)=C0(0x1)(7)-DLi5CLi/5x=I0/(AF)(x=0,t0)(8)5CLi/5x=0(x=1,t0)(9)x=0/,tl2/DLi,(7)(9):dU/dx,-,,U-t,U-t12,E-t12,(10)DLi5GITTFig.5Schematicillustrationofasinglestepofthegalvanostaticintermittenttitrationtechnique1.4(PSCA),I-t12CottrelKanamura[9]Uchina[2,6],,,,,,--DLi-Fick:5C(x,t)5t=DLi52CLi(x,t)5x2(11)DLi1,:C(x,t)=C0(t=0,0x1)(12)C(x,t)=C(x=1,t0)(13)5C(x,t)/5x=0(x=0)(14)(11),-:I(S)I=l/(Pt)1/2{(-1)nexp(-n2/S)+(-l)n+1exp[-(n+1)2/S]}(15)I(S)/I,S,IS:I=nFAD(C-C0)/l(16)S=Dt/l2(17)6-,DLi260.2V0.15V(vs.Li+/Li)-Fig.6Current-transientduringthepotentialstepexperimentalfrom0.2Vto0.15Vvs.Li+/Li(Pottedlinerepresentsthecurvecalculatedfromequ.15),,Watan-abe[10]CPRMH-NiB-Ni(OH)27GITTACLiLaNb2-O7Li1+x-7GITTACFig.7ComparisonofthechemicaldiffusioncoefficientasafunctionofxinLi1+xLaNb2O7calculatedfromtheexperimentaldatainGITTandACLaNb2O7[5]7,GITTACGITT,AC,Warburg,Warburg,Warburg7ACx0.5,x0.5,Warburg8ACCPRLixAl0.11V2O5.158ACCPRLixAl0.11V2O5.15Fig.8EvaluationofthechemicaldiffusioncoefficientoflithiumasafunctionofxinLixAl0.11V2O5.15[8]CPR,(1),,,AC,,AC9CPRPSCA[3],PSCA,,,CPRPSCA337236199912ChineseJournalofPowerSources9CPRPSCAFig.9CompositionalvariationofthechemicaldiffusioncoefficientofLithiumobtainedbybothCPRmethodandPSCAmethodCPR,(3);PSCA,,,,,,,(15),,13CPRACGITTPSCACPRGITTPSCAAC,,AC,ACWarburgPSCA,,,CPRACGITT,-,PSCA,,CPRGITTAC,,Uchina[3,6],(0.24m2/g)(0.25m2/g),,:[1],,.[J].,1997,21(4):139.[2]MACDONALDDD.Transienttechniquesinelectrochemistry[M].NewYork:PlenumPress,1977.[3]UCHINAT,MARIKAUAY,IKUTAH,etal.Chemicaldiffu-sioncoefficientoflithiumincarbonfiber[J].JElectrochemSOC,1996,143(8):2606.[4]WEPPNERW,HUGGINSRA.Deteminationofthekineticpa-rametersofmixed-conductingelectrodesandapplicationtothesystemLi3Sb[J].JElectrochemSoc,1977,124(10):1569.[5]BOHNKEC,BOHNKEO,FOURQUETJL.ElectrochemicalintercalationoflithiumintoLiLaNb2O7[J].JElectrochemSoc,1997,144(4):1151.[6]UCHINAT,ITOHT,MORIKAWAY.Anodepropertiesanddiffusioncoefficientoflithiumofpitchbasedcarbonpowder[J].DenkiKagaku,1993,61(12):1390.[7]BASUS,WORRELWL.Fastiontransportinsolides[M].NorthHollond:ElsevierScience,1979.[8]HODJEANRB,FARCYJ,RAMOSJPP.AkineticstudyoflithiumtransportinanewlithiumintercalationmaterialAl0.11-V2O5.15synthesizedviaaSol-Gelpreocess[J].JElectrochemSoc,1996,143(7):2083.[9]KANAMURAK,YUASAK,TAKEHAREZ.DiffusionoflithiumintheTiO2cathodeoflithiumbattery[J].JPowerSources,1987,20:127.[10]WATANABEK,