LiODFB电解液的高低温性能-周宏明

446()Vol.44No.620136JournalofCentralSouthUniversity(ScienceandTechnology)June2013LiODFB1,211,211(1.4100832.410083)DSCLiODFB/(EC+DMC+EMC)LiPF6/(EC+DMC+EMC)LiFePO4/G(graphiteG)60−20SEMLiODFB250LiPF6120−2060LiODFBLiPF6LiFePO4/GLiODFB−2060100LiPF6LiODFBSEILiPF6HFSEILiODFBTM911.3A1672−7207(2013)06−2230−07HighandlowtemperatureperformanceofLiODFBelectrolyteZHOUHongming1,2,LIUFurong1,LIJian1,2,FANGZhenqi1,LIYanfen1(1.SchoolofMaterialsScienceandEngineering,CentralSouthUniversity,Changsha410083,China;2.HunanZhengyuanInsitituteforEnergyStorageMaterialsandDevices,Changsha410083,China)Abstract:ThethermalstabilityofLiODFB/(EC+DMC+EMC)electrolyteandLiPF6/(EC+DMC+EMC)electrolyte,electrochemicalwindowandstabilitywiththealuminumfoilathighandlowtemperature,andthecycleperformanceofLiFePO4/G(graphite)batteryat60and−20werestudiedbyDSC,electrochemicalworkstationsandbatterytestsystem.SEMwasusedtoanalysetheanodemorphologyaftercycle,andtheinteractionmechanismbetweentheelectrolyteandelectrodeathighandlowtemperaturewasalsoinvestigated.TheresultsshowthatLIODFBelectrolyteisdecomposedat250,whileLiPF6electrolytehasadecompositiontemperatureof120.TheelectrochemicalofLiODFBelectrolyteanditsstabilitywithaluminumfoilaresuperiortothoseofLiPF6electrolyteat−20and60.LiODFBbatterywithLiFePO4/GforelectrodehasbettercapacityretentionthantheLiPF6batteryat−20and60.LiODFBelectrolyteisbenefitialtotheformationoftheSEIfilmontheGelectrode.However,LiPF6electrolytewouldgenerateHFtodestroytheSEIfilmathightemperature.Keywords:LiODFB;lithiumbattery;highandlowtemperatureperformance;thermalstability[1−4][5−8]2012−06−092012−09−01(2010FJ4061)(K1201039-11)(1969−)[e-mail]6LiODFB2231[9−11]LiODFBSEMLiODFBLiFePO4/(G)LiODFB4.5VLiPF64.4V60LiODFB10086.7%LiPF667.4%SEMLiODFBSEILiPF6LiPF6HFSEI[12]LiODFBLiODFB6.0VLiPF64.5V[13]LiODFB−20~60LiODFB−20~0LiODFBLiPF60~60LiODFBLiPF6LiODFBLiODFBLiFePO4GLiODFBLiPF6EC+DMC+EMC(1:1:1)DSCLiFePO4/GSEM11.1LiPF6()LiODFB(99.9%)EC()DMC()EMC()(10mg/L)1mol/LLiODFB/(EC+DMC+EMC)(1:1:1)LiPF6/(EC+DMC+EMC)(1:1:1)1.2LiFePO4(SP)(CMC)(SBR)GSPCMCSBRCelgard(Celgard)1.3CHI660()(Li/Li+)2.5~6.5V1mV/s−20602.5~6.5V1mV/s−2060BTS0105C8()3.6V2.5V−20601.460100LiFePO4/GDMCSEM(SIRION200FEI)1.5SDTV8.0LiODFB99.999%10/min20~50022.1DSCEC+DMC+EMC1mol/LLiODFB/(EC+DMC+EMC)1mol/LLiPF6/(EC+DMC+EMC)11150~1701EMC()442232[14]LiPF631120~135LiPF6LiFPF52150~170EMC3190~220LiPF6PF4OHCO2C2H5OC2H5CH3F[15]1LiODFB21150~170EMC2254~270LiODFB/(EC+DMC+EMC)C2H5FCO2CH3F,BF2OHLiFC2H5BF4OHLiODFBLiPF612LiPF63LiODFB1DSCFig.1DSCcurvesofdifferentelectrolytes2.22LiODFBLiPF62(a)−20LiODFBLiPF66.014.69VLiPF66.33VLiODFBLiPF62(b)60LiODFBLiPF64.203.98V1LiPF64.98VEMCDECDMCLiPF6HFLiFLiODFBLiPF625.385.11V5.625.50V2(a)20(b)601LiODFB2LiPF62−Fig.2I−EcurvesofelectrolytesLiODFBLiPF6LiODFBLiODFBLiPF6260−202−20602.3LiODFBLiPF6−33(a)−20LiODFBLiPF66.154.55VLiPF66.06VLiODFBLiPF6−20LiODFBLiPF63(b)60LiODFB−4.58~5.04V6LiODFB2233(a)20(b)601LiODFB2LiPF63−Fig.3I−EcurvesofaluminumfoilinelectrolytesEMCDECDMC5.31V5.63VLiPF6−34.63V1(1.49mA)EMCLiPF65.01V2(2.57mA)Li+LiF5.45V3(1.46mA)LiPF6HFLiPF6HF−2060LiODFBLiPF62.4LiFePO4/GLiODFBLiPF6LiFePO4/G6041LiODFB2LiPF64LiFePO4/G60Fig.4CycledischargecapacityofLiFePO4/Gbatteriesat604LiODFB60LiPF6LiODFBLiPF6100LiODFB193mA·h78%LiPF693mA·h35%LiPF660(1)LiPF6SEIHF[16]HFLiPF6(2)HFLi+LiODFB60HFLiODFBSEILi+2.5LiFePO4/GLiODFBLiPF6LiFePO4/G−2055LiODFBLiPF6−20LiODFB()4422341LiODFB2LiPF65LiFePO4/G−20Fig.5CycledischargecapacityofLiFePO4/Gbatteriesat−20214mA·h100222mA·hLiPF6208mA·h100192mA·h10LiODFBLiPF6Li+Li+LiODFBLi+SEILiODFBSEI[17]10095%LiPF6SEIHF[18]2.6LiFePO4/G6LiODFBLiPF6LiFePO4/G−20606(a)6(b)LiPF66(d)−20LiODFB10056(c)LiPF660100(a)(b)LiPF6−20100(c)LiPF660100(d)LiODFB−20100(e)LiODFB60100.6LiFePO4/G−2060Fig.6SEMimagesofgraphitebeforeandaftercycleinLiFePO4/Gbatteriesat−20and606LiODFB2235[19]LiPF6HFSEILi+HFLiPF66(e)LiODFB60100SEILiODFBODFB−SEI[20]7LiODFB2.7LiFePO4/G8LiFePO4/GLiFePO48(a)8(b)60LiODFBLiFePO4HF[11]60100LiODFB8(c)LiPF6100LiFePO4LiPF6[11]LiPF6HFHFLiFePO4LiPF68(d)8(e)−20LiODFB100LiFePO4LiPF6100LiFePO4LiODFB−20LiPF6−20LiODFBLiPF67ODFB−SEIFig.7ReactivefigureofelectrolytesaltODFB−participatinginformingSEIfilm(a)(b)LiODFB60100(c)LiPF660100(d)LiODFB−20100(e)LiPF6−201008LiFePO4/G−2060LiFePO4Fig.8SEMimagesofLiFePO4beforeandaftercycleinLiFePO4/Gbatteriesat−20and60()4422363(1)LiODFB250LiPF6120−2060LiODFBLiPF6(2)LiFePO4/GLiODFB−2060100LiPF6LiODFBSEILiPF6HFSEI[1]WangH,ShaoDG,XuL.Researchonanewtypeoflithiumbatterystringequalizationandmanagementsystem[J].AdvancedMaterialsResearch,2012,383/390:1470−1476.[2]LeeSB,JangIC,LimHH,etal.PreparationandelectrochemicalcharacterizationofLiFePO4nanoparticleswithhighratecapabilitybyasol–gelmethod[J].JournalofAlloysandCompounds,2010,491:668−672.[3]FangSH,TangYF,TaiXY,etal.Oneether-functionalizedguanidiniumionicliquidasnewelectrolyteforlithiumbattery[J].JournalofPowerSources,2011,196(3):1433−1441.[4]AngenendtK,JohanssonP.Ionicliquidbasedlithiumbatteryelectrolytes:Chargecarriersandinteractionsderivedbydensityfunctionaltheorycalculations[J].Journalof