过渡金属氮化物的锂电化学

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1、苫77G607梗里大擎硕士学位论文过渡金属氮化物的锤龟化学院系；他学系专业：姓名：攒导教螓：完成西期：物理纯学王籁傅正文剐教授2005年5月20酲攀授代码：学母；10246碱2022022——～一曼!!塑堕AbstractLithiumionbatteriescanbeusedinsomeportableelectronicdeviceswithsmal1size。ThematerialscurrentlyusedasnegativeelectrodesincommercialrechargeableLi—ionsbatteriesarebased

2、ongraphite。Inordertoimprovetheperformanceofthenegativeelectrodes，moreworkhasbeenconcentratedonthenewtypeofmaterialSsuchasalloys，oxides，transitionmetalnitridesandSOon．Transitionmetalnitridesshowhighreversibilityandlargereversiblecapacity．Ternarylithiumtransitionmetalnitridessuc

3、hasLiMnN2，Li3．；Ni．N，Li2，Fen3N，Li2￡Oo镬havebeenfoundtobeaseriesofpromiSingnegativeelectrodes．AseriesofnoveltransitionmetalnitridesofC03N、Fe剁、N13NandMndNthinfilmshavebeensuccessfullyfabricatedbyusingreactivepulsedlaserdepositionandDCdischargemethodsinanitrogenambient．Thestructure

4、，morphologyandcompositionoftheaS—depositedthinfiImswillbeinvestigated．The1ithiumelectrochemicolreactionofthinfiimswillbereportedinthisthesiS．1．CmNandFeaNthinfi1mshavebeensuccessfullypreparedby355nmpulsedlaserreactivedeposition．Theoptimumexperimentalconditionsforthepreparationo

5、fthinfilmarefoundtobeatthesubstratetemperatureof200。C，andambientnitrogengasof30Pa，thelaserenergydensityof4J／cma，theDCbiasof650Vandthedepositiontimeof2h。Thereversibledischargecapacitiesoftheas—depositedthinfiimsofC03NandFe洲rangefrom324mAh／gto420mAh／g．Thestructure，morphologyandc

6、ompositionoftheas—deposited，1ithiatedanddelithiatedC03NandFe3NthinfiImshavebeencharacterizedbyX-raydiffraction(XRD)，X-rayphotoelectronspectroscopy(XPS)andscanningelectronmicroscopyfSEM)。TheirelectrochemicalreactionwithLicannotbeexplainedbytheoxidation／reductionofnanosizedmetal

7、s．OnepartofmetallicCoandFearenitridedandreducedinthe1ithiumelectrochemicolreaction：theotherpartofCoandFeseemstoactasanactivespectatortohelpinIIAbstracttheformationanddecompositionofLi3N．2．Ni3NthinfiImshavebeensuccessfullypreparedby355nmpulsedlaserreactiredepositionunderthesame

8、experimentaleonditionsasthefabricationofC03NandFejNthinfilms．