电池电极中的固态电解质技术

TheInternationalConferenceontheFrontierofAdvancedBatteries,CIBF2014Solvent-DependentSolidElectrolyteInterphasesonNongraphiteElectrodes,31,2,Outline1.TheeffectofFECandSEIstructureonSi.,byXPS,ToF-SIMSinthecaseofNexelion,O,O,O,F2.Furtherimprovementbyelectrolytesystem.SEIstructureatseveralcharge/dischargecut-offvoltageusingseveralelectrolytesystem.,Capacity(mAh/cm3),Capacity(mAh/g),3,ComparisonofvariousnegativeelectrodematerialsforLiionbatteriesForthehighcapacitybatterySiandSnareverypromisingnegativeelectrodematerials.Oneoftheproblemsispoorcycleperformance.31,100020003000,4000,1000C0,SnandSi3000SnSi2000,Lix3(Volume),31,4,FEC,ImprovementoncycleperformancebynewelectrolytematerialFECFEC/DEC,EC/DEC,Si(EBdeposition)/LiCoinCellElectrolyte:EC/DEC=1/1,1MLiPF6FEC/DEC=1/1,1MLiPF60V(CCCV)-1.2V(CC)(vs.Li)CC0.3mA/cm225,O,O,O,F,31,5,WhyFECissoeffective?InvestigationofSisurfaceSEI(SolidElectrolyteInterphase)XPSElementinformationQuantitativedepthinformationToF-SIMSChemicalstructureinformation,RelativeIntensity,RelativeIntensity,Sputtertime(min),Sputtertime(min),Oxygen:FEC/DECEC/DECThicknessofSEI:FEC/DEC(DFEC,VC),Intensity(arb.u.),Intensity(arb.u.),31,25,AmountofPhosphorus,AmountofFluorine,ECFECDFECVC,ECFECDFECVC,XPSanalysisofsolventdecompositionproducts4.25Vchargestate,AmountofPhosphorusAmountofFluorine,ECDFECFEC,VCDFEC,FECDFEC,VC,Intensity(arb.u.),Intensity(arb.u.),31,682,684,686,688,690,692,694,FEC,EC680,26/20,AmountofLithiumFluoride,XPSF1sphotoelectronspectraLiFVCDFEC,ECFECDFECVC,XPSanalysisofsolventdecompositionproducts4.25Vchargestate,BindingEnergy(eV)BindingEnergy(eV)FluorinearefromLiFandP-Fcompounds.,AmountofLiF,FECDFECECVC,26,31,SEIcharacteristics,O,n,nn,FEC,DFEC-basedELVC-basedEL,EC-basedEL,OriginEC,DEC&LiPF6decomposition,PreferentialreductionofFEC,DFECPreferentialreductionofVC,MaincomponentsROLiLi2CO3POxFy,LiFO,OFEC/DFEC/VC-basedEL:PreferentialreductionofDFEC/FEC/VCSuppressfurtherELdecompositionFormationofprotectiveSEIisakeyfactor.,27,AtomicConcentration(at.%),31,FEC-basedEL,EC-basedEL,VC-basedEL,28,CellVoltage(V),CellVoltage(V),CellVoltage(V),SurfacechangeduringdischargeprocessXPSsurfacecomposition,IncreaseinamountofSiasDODincreasesDecreaseofSEIduringdischargeprocess,DFEC-basedEL,CellVoltage(V),Li1s,C1s,O1s,F1s,Si2p,P2p,Siamount(At.%),31,CellVoltage(V)VC-basedEL:NochangeinamountofSiVC-derivedSEIisverystable.VCDFECFECECSEIstabilityisakeyfactor.,29/29,SEIstabilityduringdischargeprocessTrendofSiamountduringdischargeprocessEC-basedELFEC-basedELDFEC-basedELVC-basedEL,29,31,ConclusionsFECisgoodsolventoradditiveforSiandSn-basedelectrodeslithiumionbattery.,SEIofFECincludingelectrolytehasLiFandpolyene.,NewelectrolytesystemsforSielectrodeswereinvestigated.,EffectofelectrolytesystemsoncyclelifeFEC-basedELVC-basedELEC-basedELEffectofdischargecut-offvoltageoncyclelifeVC-basedELFEC-basedELEC-basedELDetailsoftheSEIcharacteristicsduringthecharge-dischargeprocesswereinvestigated.SEIincreasesduringthechargeprocess.SuppressionoffurtherELdecompositionbyprotectiveSEIduetopreferentialreductionofFEC,DFEC,VC.ProtectiveSEIonSielectrodecontributestocyclelifeimprovement