锂离子电池的电化学阻抗谱分析_庄全超

22620106PROGRESSINCHEMISTRYVol.22No.6Jun.20102009720099*973No.2009CB220102No.ON080282[e-mail]@xmu.edu.cn*1111121.2211162.361005EIS/。EIS、、SEI。SEIO646O657.1TM911A1005-281X201006-1044-14DiagnosisofElectrochemicalImpedanceSpectroscopyinLithiumIonBatteriesZhuangQuanchao1XuShoudong1QiuXiangyun1CuiYongli1FangLiang1SunShigang21.SchoolofMaterialsScienceandEngineeringChinaUniversityofMiningandTechnologyXuzhou221116China2.StateKeyLabforPhysicalChemistryofSolidSurfacesDepartmentofChemistryXiamenUniversityXiamen361005ChinaAbstractElectrochemicalimpedancespectroscopyEISisoneofthemostpowerfultoolstoanalyzeelectrochemicalprocessesoccurringatelectrode/electrolyteinterfacesandhasbeenwidelyusedtoanalyzetheinsertion/desertionprocessoflithiumionintheintercalationelectrodeforlithiumionbattery.InthispapertheascriptionofeachtimeconstantofEISspectraisdiscussedbasedonanalyzingthecommonEISfeaturesofintercalationelectrode.Thekineticparametersinthelithiumioninsertion/desertiondependentontemperatureandelectrodepolarizationsuchasthechargetransferresistancetheelectronicresistanceofactivatedmaterialtheresistanceofSEIfilmthatlithiumiontransferringthrougharealsodiscussedbasedonthetheoreticalanalysis.KeywordslithiumionbatterieselectrochemicalimpendancespectroscopyEISSEIfilmelectronicconductivitychargetransferresistanceContents1Introduction2ThecommonEISfeaturesofintercalationelectrode3Theanalysisofelectrochemicalimpedancespectr-oscopy3.1Theanalysisofhigh-frequencyarc3.2Theanalysisofmediumtohigh-frequencyarc3.3Theanalysisofmedium-frequencyarc3.4Theanalysisoflow-frequencystraightline3.5Theanalysisofthelowest-frequencydomain4Conclusion6·1045·12090、、、、。。。、1—3。、、solidelectrolyteinterfaceSEI、、45。electrochemicalimpedancespectroscopyEISEIS。EIS、。EIS6—9。EISEIS、、SEI。2/。/。EIS。adsorptionmodelsurfacelayermodel。adatommodeladionmodelBruce1011LiTiS2。10—13123。EIS3。SEI14SEI。Thomas15LiCoO2。SEIinsertion-ion。EIS3SEI·1046·22。Aurbach16—19SEISEI20—23、SEI、、1。AurbachEIS4SEI。Aurbach。1EIS22Fig.1Equivalentcircuitusedforanalysisofimpedancespectraofthelithiumioninsertion/desertionintheintercalationelectrode22Aurbach。Aurbach。Barsoukov24252。1、2SEI3/45。BarsoukovEIS538110kHz、、、EISRs2RSEI/CSEI。RSEISEI3Rct/Cdl。RctCdl4WarburgZW50.01HzRb/CbCint。RbCb6·1047·Cint。2Barsoukov24Fig.2Pictorialrepresentationmodelforlithiumioninsertion/desertionintotheintercalationelectrodeproposedbyBarsoukovetal2438Fig.3Typicalimpedancespectraofintercalationelectrode8、。。、、26。。。、Barsoukov。。Barsoukov。Barsoukov-。427Fig.4Pictorialrepresentationmodelforlithiumioninsertion/desertionintotheintercalationelectrode2727Barsoukov。4Barsoukov。4SEI·1048·225LiMn2O4EIS27Fig.5TheEISofspinelLiMn2O4electrodeatdifferentpotentialsinthefirstchargeprocess272829。EISBarsoukov5Re/CeRe。SEISEISEI。EISSEIEIS。6·1049·EIS105—10－2HzEIS0.01Hz50μHzEIS41SEI234。ReEISRe/CeEISRSEI/CSEI、Rct/Cdl。EISEIS30—37。EISRct/Cdl38—41。RSEIEISRSEI/CSEI。EIS4SEIRe/CeRSEI/CSEIEIS。。EISLiMn2O4275。EIS42—44EIS。EIS45—474849。3EIS。、。、、5051。EIS。3.1EISSEIHFARSEI/CSEI。HFA。HFASEIHFA。52—54EISHFAHFAHFA。5556。EISEISHFAHFA、576。5859HFA。RSEICSEISEI·1050·226Nyquist57Fig.6Nyquistplotsofgraphiteelectrodeduringthefirstlithiationatvariouspotentials57SEI、、EISSEI。3.1.1RSEICSEISEISEI60—62SEIRSEICSEISEIρε12。RSEI=ρl/S1CSEI=εS/l2lSEIS。ρ、εSRSEICSEISEIRSEICSEISEI。3.1.2SEIRSEISEI6364SEI。SEI1SEISEI2SEISEI。ΔVM－S12SEIρe。icorr=ΔVM－S/ρel3lSEIdldt=Kicorr4K34dldt=KΔVM－Sρel55l=l20+2KΔVM－Sρe·()t1/26t=0l=l0。SEI7icorr=FDC0l7DSEIC0SEI。74dldt=KFDC0l8l=l20+2KFDC0t1/2969SEI。SEI。ρeDlSEI、SEI。LiMn2O4RSEI65。6·1051·3.1.3RSEISEISEI10636466。i=4zFacνexp－W/RTsinhazFE/RT10athejump'shalfdistanceνz1WcEFFaraday。SEIη=ηSEI=El11ηlSEI。10i=4z2F2a2cν/RTlexp－W/RTη12SEIRSEIRSEI=RTl/4z2F2a2cνexpW/RT1313lnRSEI=lnRTl/4z2F2a2cv+W/RT1414lnRSEI-T－1W。14LiCoO21MLiPF6-EC∶DEC∶DMC1MLiPF6-PC∶DMC+5%VCSEI37.7426.55kJ/mol67。3.2EISRe/Ce。Re。RσR=SσL15LS。15Re。EIS。3.2.1ReArrheniusσ=Aexp－Ea/RT16AEa。1516R=SALexpEa/RT1717lnR=lnSAL+EaRT1818lnRe-T－1Ea。15LiCoO21MLiPF6-EC∶DEC∶DMC1MLiPF6-PC∶DMC+5%VC39.08kJ/mol53.81kJ/mol67。3.2.2RenpRe。LiCoO2pEg=2.7eV68—70。LixCoO2x1LiCoO2p=1－x19p。x0.75LixCoO2LixCoO2。68。LiCoO231LixCoO223LixCoO2。pσσ=pqμ20μq。LixCoO2LangmuirinsertionisothermxE·1052·2271x/1－x=expfE－E021f=F/RTFRTEE0。1921p=1/1+expfE－E022152022lnR=lnS/qμl+ln1+expfE－E023ln1+expfE－E0lnR=ln2S/qμl+12fE－E02424lnR-E。plnReE31LixCoO2lnRe-E2lnReE3LixCoO2lnRe-E72。LiCoO2pLiMn2O4nMn3+Mn4+73—75。1Mn3+2Mn-Mn。Mn3+Mn4+LiMn2O4Mn-MnLiMn2O4。LiMn2O4Re。LiMn2O4。Mn-MnLiMn2O4。LiMn2O4LiMn2O4LiCoO2。3.3EISRct/CdlRctCdl。CdlRctLiCoO2Rct。3.3.1RctLiCoO21－xLi++1－xe+LixCoO2LiCoO225cT1－xM+cT1－xLixCoO2xintercalationlevelcTLiCoO2mol/cm3。cTxcTxrfrb7677rf=kfcT1－xM+26rb=kbcTx27i=rf－rb=nFcTkf1－xM+－kbx28n。LiCoO2ΔGintΔGint=a+gx29ag、。LiCoO2ΔGintkfkb76kf=k0fexp－αnFE+ΔGint[]RT30kb=k0bexp1－αnFE+ΔGint[]RT316·1053·αkfkbArrheniuskf=Afexp－ΔG0c()RT32kb=Abexp－ΔG0a()RT3328、3031i=nFcTk0f1－xM+exp－αnFE+ΔGint[]RT－nFcTk0bxexp1－αnFE+ΔGint[]RT34E=Eei=0i0i0=nFcTk0f1－xM+exp－αnFE+ΔGint[]RT=nFcTk0bxexp1－αnFE+ΔGint[]RT35i0=nFcTk0M+1－α1－x1－αxα36k0E0k0=k0fexp－αnFE0+ΔGint[]RT=k