锂离子电池硅2f碳复合负极材料的制备与性能分析

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1、ABSTRACTSiljconisr。gardedasoneofthemostpromisi“ganodesforthenextgeneratjonofhighene。gydensl哼Lj—ionbatte^esduetoitslargeIheoretlcalsPecI缸capacityandlowLi-msenionpotential(vsLi几i+)Inthisthesis，t11eresearchprocessofaTlodesforlithium-ionbanerieshasbeensummariz

2、edindetaIlandthree‘ypesofsilicon／乒aphite，carboncompositeshavebeensynthesizedbysever甜methodsThetIlreecompositesareseparatelysilico“sphe打calnanJralgraphite／carboncomposite，silicon／porousgraphite／carboncompositeandsilicon／nakegraphite／carbonsphericaJcomposite

3、Andt11emorphoIogies，phasecomponentsandelectmchemicaIpropeniesoft11esematerialsalsohavebeeninvestigaled．Theef话ctsofsiliconcontent，carbonsource，disDersjonmethod，calcjnatjontemperatureandpyroly“ccarboncontenIonthestructure，morphologyandelectrochemjcalpropenie

4、sofsi／ccompositeshavebeenstudledAndtheoptimumconditionshavebeenobtainedUndert11eoptimumconditions，silico“sphericalnaturalgraphit“carboncomposite(siljcon：graphite：carbon=25：5025)wi山thebestelectrochemicalperformanceissynthesizedviatwiceuItrasonic·mechanicalm

5、ixingandsubs。quen‘pyrolysis(800℃，2h)Therawmatenalsofthecompositearenallo—s1，sphericalnaturalg‘印hiteandvinylIdenechlorlde(cPVc)，andthecompositeshowsaninitialreversiblec8pacityof71944mA}吨withaninitialcoulombicemclencyof6322％，a11dareversiblecapacityof44680mAh

6、／gwithac3pacityretentionrateof6210％aRer20cyclesLiquidphaseoxidatlonofsPhericaInan】raIgraphitehasbeenusedtoobtai“Porousgraphjteandsilicon／porou5g。印hite，carboncompositehasbeenpreparedFirstofall，theeffectsofdi位rentoxidantsanddi位rentamountsofoxidantonthestnlct

7、ure，morphoIogyandelectrochemicalpmpeniesofporousgraphitehavebeensmdiedTheresultsshowthatporousgraphiteoxldjzedbyK2c‘207andH2s04hasalotofmicronporesonthesurface，andpresentshigherdischargecapac时(120650mAh／曲andch8rgecapaclty(44547mAh／g)thansphericaJnaturalgra

8、phitewithoutoxidatjon，butitsinitlalcoulombicemcienoyisonly3692％柚d中南大学碰L学位论文thereVersiblecapacityfort}le20【}1。ycleisonly35436mAh儋withacapacJtyretentlonrateof7955％Then，smcon／porousgraphlte／carboncompositejssynt