高电压正极材料li1-xcoo2x=0.75的电子结构

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1、Cleanenergyeconomicsisoneofthemostimportantgoalspursuedbythehumancommunityinthe21thcentury．Inthiscontext，theexplorationandapplicationofLi-ionbatterieshaveattractedmoreandmoreattentions．Itsapplicationhasbeenrapidlyexpandedfromtheinitialmobilecommunicationequipment

2、stoavarietyofportableelectronicproductsthatrelatedtopeople’Sdailylifeandentertainment，military，aerospaceandmedicalcare．Thedevelopmentintheseareasspurredanever-higherrequirementsontheenergydensity,reversibilityandsafetyoflithium-ionbattedes．Inordertomeetthegrowing

3、needsofenergyconversionandreservation，searchingfornewinnovativeelectrodematerialsandimprovementoftheexistedoneshasbecometheon—goingresearchhotspotrecently．Tofurtherincreasethecapacityofthewell—developedcathodematerialLiC002forlithiumionbatteriesisanimportantdirec

4、tionofresearch．Inthispaper,thefirst-principlescalculationsbasedondensityfunctionaltheoryhasbeenperformedtoinvestigatethegeometricandelectronicstructuresofLil．YC002(x20．75)withhighamountofdeintercalationofLi，inthepurposeofprovidinginformationforunderstandingthenat

5、ureoftheelectronicstructuresofthishigh-voltagematerial．ThecalculationsshowthatCoiSvalence3+inmaterialLiC002．ⅥmensmallamountofLiisextractedfromLiC002．somepartofC03+aretransformedtoC04+owingtolosinganelectron．WhenlargeamountofLi似20．75)areextracted，howeveLpartofelec

6、tronsofO一2porbitalarealsolosed，exceptforthevalencechangefromC03+toC04+．Therefore，twodifferentoxidationstatesofoxygen，O1and02．TheO1oxygentakes1／3ofthetotaloxygenwhile02oxygenmakeuptheleft2／3．Thereareobviousdifferencesinthebondlengthsbetweendifferentvalencestatesof

7、Coanddifferenttypesofoxygen．Moreelectronaccumulationsbetween万方数据C04+and0ionsarefound，ascomparedwiththosebetweenCo”andOions．TheinteractionsbetweenC04+and0ionsarealsostrongerthanthosebetweenC03+and0ions．Keywords：Lil．xC002；Electronicstructures；First-principlescalcul

8、ations；GGA+U万方数据目录第一章绪论．11．1锂离子电池简介．21．2锂离子电池的原理和特性．61．2．1锂离子电池工作原理．61．2．2锂离子电池特性71．3锂离子电池电极材料．91．3．1正极材料．91．3．2负极材料141．4论文框架l5参考文献．16第二章理论计算方法2l2．1密度泛函理论．．212