锂离子二次电池界面过程的红外光谱研究

232/320113PROGRESSINCHEMISTRYVol.23No.2/3Mar.201120109201011*No.210031022083300521021002973No.2009CB220102[e-mail]*361005/、/、。。、。FTIRS、。O646.21O657.33A1005-281X201102/3-0349-08InterfacialProcessesofLithiumIonBatteriesbyFTIRSpectroscopyLiJuntaoFangJunchuanSuHangSunShigangSchoolofEnergyResearchStateKeyLaboratoryofPhysicalChemistryofSolidSurfacesCollegeofChemistryandChemicalEngineeringXiamenUniversityXiamen361005ChinaAbstractLithium-ionbatteriesLIBsareoneoftheimportantelectrochemicalpowersourcesforlow-orzero-emissionhybridelectricalandelectricalvehiclesenergy-efficientcargoshipsandlocomotivesandaerospaceinthemodernsociety.Thedifficultiesinmasteringtheelectrode/electrolyteinterfacehavesloweddowntheprogressofLIBs.Interfacialprocessesoflithiumionbatteriesincludemainlyinsertion/extractionoflithiumionsolvation/desolvationoflithiumwithsolventsformationandvariationofsolidelectrolyteinterphaseSEIlayeranddecompositionofelectrolyte.Interfacialprocessesdirectlyaffecttheefficiencyofelectrochemicalenergyconversionandstoragesuchasthecyclingabilitythelifetimeandthereversiblecapacityaswellasthesafetyissueoflithiumionbatteries.ThecharacterizationoftheinterfaceprocessesatamolecularlevelbyFTIRspectroscopyisoneofthekeysubjectsasitishelpfulfortheimprovementtheperformanceoflithiumionbatteriesanddevelopmentofnon-aqueoustheory.RecentprogressesabouttheapplicationofFTIRspectroscopyinlithiumionbatteriesarereviewed.ThisreviewputemphasisonathecharacterizationofchemicalcompositionandvariationofSEIlayeroncycledoragedelectrodematerialsbyexsituFTIRspectroscopyandbtheinvestigationofdecompositionofelectrolyteformationofSEIlayerandtheinsertion/extractionoflithiumionbybothin-situFTIRreflectionspectroscopyandinsituFTIRtransmissionspectroscopy.KeywordsFTIRspectroscopylithiumionbatteryinterfacialprocesses·350·23Contents1Introduction2CharacterizationofinterfacialreactionsbyexsituFTIRspectroscopy2.1CharacterizationofinterfacialreactionsonAnodes2.2CharacterizationofinterfacialreactionsonCathodes3CharacterizationofinterfacialreactionsbyinsituFTIRreflectionspectroscopy3.1PrincipleofinsituFTIRreflectionspectroscopy3.2OverviewofinsituFTIRreflectionspectroscopyinlithiumionbatteries3.3InvestigationofinterfacialreactionsonseveralanodesbyinsituFTIRspectroscopy4CharacterizationofinterfacialreactionsbyinsituFTIRtransmissionspectroscopy5Conclusion1、、1—4。、/、solidelectrolyteinterphaseSEI。、、5—7。、。FTIRS、8。。SEI。FTIRS/SEI。2FTIRSSEI。SEI。SEI9—11SEISEI。SEI12。FTIRS。FTIRS。FTIRS。FTIRSKBrFTIRS。FTIRSdiffusereflection、IRARSATR。FTIRS。IRARS。FTIRS、。FTIRSLi2CO3ROCO2LiR。SEIROLi、LiOH、LiF。2.1FTIRSFTIRSSEI13—24。Yang13FTIRSSEI。EC、DECDMCSEICH2OCO2Li2、C2H5OCO2LiLi2CO3EC-DECEC-DMCSEICH2OCO2Li2EC。IRARSLiPF6/EC-DMCSEI2/3·351·ROCO2Li14。Naji15FTIRSLiClO4/ECSEIROCO2LiLi2CO3Li2CO31.0—0.8VROCO2Li0.8V。Aurbach16EC-DMCSEIROCO2LiEC。ROCO2LiLi2CO3HFLiF。18650-LiPF6/EC-EMCROCO2Li10—15ROCO2LiHFLiF17。Lee02040℃SEI18。SEIROCO2LiLi2CO3ROCO2LiLi2CO3ROCO2LiLi2CO3。AurbachLiSEI16。LiPF6/EC-DECSnO20.8VSEIROCO2LiLi2CO3LiClO4/PC-DMCLi2CO325。LiIRARSLiClO4/PCCr2O3SEILi2CO326。LiPF6/EC-DMCSongATR-FTIRSSnSEIPF-ROCO2Li27LiSn-CoSEIROCO2Li28。2.2FTIRS2.2.1SEISEI29—31。Ostrovskii29FTIRSLiNi0.8Co0.2O2LiMn2O4。LiNi0.8Co0.2O2LiMn2O4PCEC-DMC。LiNi0.8Co0.2O2LiMn2O4。、SEI。LiNi0.5Mn0.5O2LiMnPO4LiPF6/EC-DMCFTIRS130。LiNi0.5Mn0.5O2Li2CO3OCO2ROCO2MM=LiNiMn。LiMnPO4LiFePO4LiMnPO4。LiMPO4。130℃LiPF6/EC-DMCaLiNi0.5Mn0.5O2bLiMnPO430Fig.1FTIRspectrameasuredindiffusereflectancemodeforthepristineandagedaLiNi0.5Mn0.5O2andbLiMnPO4powdersinstandardLiPF6/EC-DMCat30℃30Kerlau31LiNi0.8Co0.15Al0.05O2LiPF6/EC-EMC25。LiNi0.8Co0.15Al0.05O2ROCO2LiEC。LixPFyLixPFyOzLiF·352·23LiPF6LiFPF5。PF5。2.2.2FTIRS1732。Aurbach17FTIRSLiCoO2LiPF6/EC-EMC。LiCoO2PVdFνC—F1180cm－1δC—H1400cm－1。1800—17001600—500140013001130890cm－1。。Xu32FTIRSLiCoO2LiPF6/EC+DEC。LiCoO2LixPOy。Wu33Li1.05Mn1.96O4SEISEILi1.05Mn1.96O4ROCO2LiLi2CO3。3FTIR3.120803435。、、、、、。20FTIR3637。FTIRS。3123、。FTIRS/。ATR38—40。ATR3839。1—10μm。40。2FTIR41—44。241—44Fig.2SchematicillustrationoftheelectrochemicalinsituFTIRspectroscopiccellsforlithiumionbatteries41—443.2Morigaki45—47FTIRSLi。EC+DMCMCMBSEIROCO2LiSEI。Baek48ATR-FTIRSSnLiPF6/EC-DMC。Sn1.0VP—FSnPF－20.63V0.1VP—F。Santner37FTIRS2/3·353·SEISEI。Kanamura4249FTIRSLiCoO2、LiMn2O4LiNi1/2Mn3/2O4SEI。EC-DECSEI。LiCoO2Co4.2V。LiMn2O4LiNi1/2Mn3/2O4-。Aurbach50NiAu。SEI1.5VECCH2OCO2Li2。LiPF6Li。Ikezawa41CuLiClO4/PC。CuPCPC。Li+PC4Li+PC3PCPCPC。3.33.3.1FTIRS。/。Lisol+nsol。Lisol+nLi+…COLisol+nCOCOνCOLisol+nC—O51—53。3ECDMC28。Lisol+n。4aSnLiPF6/EC+DMCFTIR44。18031766cm－1ECυCO1757cm－1DMCυCO。127911581071cm－1υC—O。。178117711726cm－1Lisol+nυCO3aECbDMC28Fig.3SchematicillustrationofmoleculestructuresofthesolvatedDMCaandECbwithlithiumions284FTIRaSnbSn-CocdCu1MLiPF6/EC+DMC1∶1142844Fig.4InsituFTIRSofSnaSn-CoalloybgraphitecandCudelectrodein1MLiPF6/EC+DMC1∶1duringthelithiationprocess1428441322、11991088cm－1Lisol+nυC—OLisol+n。842cm－1PF－6SnPF－6SnLisol+nSnLisol+n。4dCuSn·354·23FTIR28。Cu。FTIRSSn-CoLiPF6/EC+DMC1428。3.3.2FTIRSSEI。5SnLiPF6/EC+DMC1.5V1.1VFTIR44。1768、1723cm－11325、1201cm－1Lisol+n