锂离子电池容量衰减机理和副反应翻译个人翻译的外文文献.docx

锂离子电池容量衰减机理和副反应翻译个人翻译的外文文献.docx

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锂离子电池容量衰减机理和副反应翻译个人翻译的外文文献

CapacityFadeMechanismsandSideReactionsin

Lithium-IonBatteries

锂离子电池容量衰减机机理和副反应

PankajAroratandRalphE。

White＊

作者:

PankajAroratandRalphE.White＊

CenterForElectrochemicalEngineering，DepartmentofChemicalEngineering,UniversityofSouthCarolina，Columbia，SouthCarolina29208，USA

美国,南卡罗来纳，年哥伦比亚29208,南卡罗来纳大学，化学工程系,中心电化学工程

ABSTRACT

Thecapacityofalithium—ionbatterydecreasesduringcycling。

Thiscapacitylossorfadeoccursduetoseveraldifferentmechanismswhichareduetoorareassociatedwithunwantedsidereactionsthatoccurinthesebatteries。

Thesereactionsoccurduringoverchargeoroverdischargeandcauseelectrolytedecomposition,passivefilmformation,activematerialdissolution,andotherphenomena.Thesecapacitylossmechanismsarenotincludedinthepresentlithium-ionbatterymathematicalmodelsavailableintheopenliterature.Consequently，thesemodelscannotbeusedtopredictcellperformanceduringcyclingandunderabuseconditions.Thisarticlepresentsareviewofthecurrentliteratureoncapacityfademechanismsandattemptstodescribetheinformationneededandthedirectionsthatmaybetakentoincludethesemechanismsinadvancedlithium-ionbatterymodels.

Introduction

Thetypicallithium—ioncell（Fig.1）ismadeupofacokeorgraphitenegativeelectrode,anelectrolytewhichservesasanionicpathbetweenelectrodesandseparatesthetwomaterials,andametaloxide（suchasLiCoO2,LiMn2O4，orLiNiO2）positiveelectrode。

Thissecondary（rechargeable）lithium—ioncellhasbeencommercializedonlyrecently.Batteriesbasedonthisconcepthavereachedtheconsumermarket,andlithium—ionelectricvehiclebatteriesareunderstudyinindustry。

Thelithium—ionbatterymarkethasbeeninaperiodoftremendousgrowtheversinceSonyintroducedthefirstcommercialcellin1990。

Withenergydensityexceeding130Wh/kg（e。

g.，MatsushitaCGR17500）andcyclelifeofmorethan1000cycles（e.g。

Sony18650）inmanycases,thelithium-ionbatterysystemhasbecomeincreasinglypopularinapplicationssuchascellularphones,portablecomputers，andcamcorders.Asmorelithium—ionbatterymanufacturersenterthemarketandnewmaterialsaredeveloped,costreductionshouldspurgrowthinnewapplications.SeveralmanufacturerssuchasSonyCorporation，SanyoElectricCompany，MatsushitaElectricIndustrialCompany,MoliEnergyLimited，andA＆TBatteryCorporationhavestartedmanufacturinglithium—ionbatteriesforcellularphonesandlaptopcomputers.Yoda1hasconsideredthisadvancementanddescribedafuturebatterysocietyinwhichthelithium—ionbatteryplaysadominantrole.

Severalmathematicalmodelsoftheselithium-ioncellshavebeenpublished。

Unfortunately，noneofthesemodelsincludecapacityfadeprocessesexplicitlyintheirmathematicaldescriptionofbatterybehavior.Theobjectiveofthepresentworkistoreviewthecurrentunderstandingofthemechanismsofcapacityfadeinlithium-ionbatteries.Advancesinmodelinglithium-ioncellsmustresultfromimprovementsinthefundamentalunderstandingoftheseprocessesandthecollectionofrelevantexperimentaldata.

Someoftheprocessesthatareknowntoleadtocapacityfadeinlithium—ioncellsarelithiumdeposition（overchargeconditions）,electrolytedecomposition,activematerialdissolution，phasechangesintheinsertionelectrodematerials，andpassivefilmformationovertheelectrodeandcurrentcollectorsurfaces.Quantifyingthesedegradationprocesseswillimprovethepredictivecapabilityofbatterymodelsultimatelyleadingtolessexpensiveandhigherqualitybatteries。

Significantimprovementsarerequiredinperformancestandardssuchasenergydensityandcyclelife,whilemaintaininghighenvironmental,safety，andcoststandards。

Suchprogresswillrequireconsiderableadvancesinourunderstandingofelectrodeandelectrolytematerials,andthefundamentalphysicalandchemicalprocessesthatleadtocapacitylossandresistanceincreaseincommerciallithium—ionbatteries.Theprocessofdevelopingmathematicalmodelsforlithiumioncellsthatcontainthesecapacityfadeprocessesnotonlyprovidesatoolforbatterydesignbutalsoprovidesameansofunderstandingbetterhowthoseprocessesoccur。

PresentLithium-IonBatteryModels

Thedevelopmentofadetailedmathematicalmodelisimportanttothedesignandoptimizationoflithiumsecondarycellsandcriticalintheirscale—up。

Westdevelopedapseudotwo—dimensionalmodelofasingleporousinsertionelectrodeaccountingfortransportinthesolutionphaseforabinaryelectrolytewithconstantphysicalpropertiesanddiffusionoflithiumionsintothecylindricalelectrodeparticles.Theinsertionprocesswasassumedtobediffusionlimited，andhencecharge-transferresistanceattheinterfacebetweenelectrolyteandactivematerialwasneglected。

LaterMaoandWhitedevelopedasimilarmodelwiththeadditionofaseparatoradjacenttotheporousinsertionelectrode。

Thesemodelscoveronlyasingleporouselectrode；thus，theydonothavetheadvantagesofafull-cell—sandwichmodelforthetreatmentofcomplex，interactingphenomenabetweenthecelllayers.ThesemodelsconfinethemselvestotreatinginsertionintoTiS2withthekineticsfortheinsertionprocessassumedtobeinfinitelyfast。

SpotnitzaccountedforelectrodekineticsintheirmodelfordischargeoftheTiS2,intercalationcathode。

Thegalvanostaticchargeanddischargeofalithiummetal/solidpolymerseparator/insertionpositiveelectrodecellwasmodeledusingconcentrated—solutiontheorybyDoyle.Themodelisgeneralenoughtoincludeawiderangeofseparatormaterials，lithiumsalts，andcompositeinsertionelectrodes。

Concentrated-solutiontheoryisusedtodescribethetransportprocesses,asithasbeenconcludedthationpairingandionassociationareveryimportantinsolidpolymerelectrolytes。

Thisapproachalsoprovidesadvantagesoverdilutesolutiontheorytoaccountforvolumechanges.Butler—Volmer—typekineticexpressionswereusedinthismodeltoaccountforthekineticsofthecharge—transferprocessesateachelectrode。

ThepositiveelectrodeinsertionprocesswasdescribedusingPick’slawwithaconstantlithiumdiffusioncoefficientintheactivematerial。

Thevolumechangesinthesystemandfilmformationatthelithium/polymerinterfacewereneglectedandaverysimplisticcaseofconstantelectrodefilmresistanceswasconsidered。

Long—termdegradationofthecellduetoirreversiblereactions（sidereactions）orlossofinterfacialcontactisnotpredictableusingthismodel.

Fullerdevelopedageneralmodelforlithiumioninsertioncellsthatcanbeappliedtoanypairoflithium-ioninsertionelectrodesandanybinaryelectrolytesystemgiventherequisitephysicalpropertydata.Fullerworkdemonstratedtheimportanceofknowingthedependenceoftheopen-circuitpotentialonthestateofchargefortheinsertionmaterialsusedinlithium-ioncells.Theslopesofthesecurvescontrolthecurrentdistributioninsidetheporouselectrodes,withmoreslopedopen—circuitpotentialfunctionsleadingtomoreuniformcurrentdistributionsandhencebetterutilizationofactivematerial.OptimizationstudieswerecarriedoutfortheBellcoreplasticlithium—ionsystem。

Themodelwasalsousedtopredicttheeffectsofrelaxationtimeonmultiplecharge—dischargecyclesandonpeakpower.

Doylemodifiedtheduallithium-ionmodeltoincludefilmresistancesonbothelectrodesandmadedirectcomparisonswithexperimentalcelldatafortheLiC6-LiPF6，ethylenecarbonate/dimethylcarbonate（EC/DMC）,KynarFLEX-ILiyMn2O4system.Comparisonsbetweendataandthenumericalsimulationssuggestedthatthereisadditionalresistancepresentinthesystemnotpredictedbypresentmodels。

Thedischargeperformanceofthecellswasdescribedsatisfactorilybyincludingeitherafilmresistanceontheelectrodeparticlesorbycontactresistancesbetweenthecelllayersorcurrent—collectorinterfaces。

OneemphasisofthisworkwasintheuseofthebatterymodelforthedesignandoptimizationofthecellforparticularapplicationsusingsimulatedRagoneplots。

Thermalmodelingisveryimportantforlithiumbatteriesbecauseheatproducedduringdischargemaycauseeitherirreversiblesidereactionsormeltingofmetalliclithium,ChenandEvanscarriedoutathermalanalystsoflithiumionbatteriesduringcharge-dischargeandthermalrunawayusinganenergybalanceandasimplifieddescriptionoftheelectrochemicalbehaviorofthesystem。

Theiranalysisofheattransportandtheexistenceofhighlylocalizedheatsourcesduetobatteryabuseindicatedthatlocalizedheatingmayraisethebatterytemperatureveryquicklytothethermalrunawayonsettemperature,abovewhichitmaykeepincreasingrapidlyduetoexothermicsidereactionstriggeredathightemperature。

PalsandNewmandevelopedamodeltopredictthethermalbehavioroflithiummetal-solidpolymerelectrolytecellsandcellstacks.Thismodelcoupledanintegratedenergybalancetoafullcell—sandwichmodeloftheelectrochemicalbehaviorofthecells.Bothofthesemodelsemphasizedtheimportanceofconsiderationsofheatremovalandthermalcontrolinlithiumpolymerbatterysystems.

VerbruggeandKochdevelopedamathematicalmodelforlithiumintercalationprocessesassociatedwithacylindricalcarbonmicrofiber.Theycharacterizedandmodeledthelithiumintercalationprocessinsingle-fibercarbonmicroelectrodesincludingtransportprocessesinbothphasesandthekineticsofchargetransferattheinterface.Theprimarypurposeofthemodelwastopredictthepotentialasafunctionoffractionaloccupancyofintercalatedlithium.Theoverchargeprotectionfo