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ID:39403294
大小:1.28 MB
页数:60页
时间:2019-07-02
《过渡金属氮化物的锂电化学 硕士学位论文》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
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—ionsbatteriesar
2、ebasedongraphite。Inordertoimprovetheperformanceofthenegativeelectrodes,moreworkhasbeenconcentratedonthenewtypeofmaterialSsuchasalloys,oxides,transitionmetalnitridesandSOon.Transitionmetalnitridesshowhighreversibilityandlargereversiblecapacity.Ternarylithiumtransitionmeta
3、lnitridessuchasLiMnN2,Li3.;Ni.N,Li2,Fen3N,Li2£Oo镬havebeenfoundtobeaseriesofpromiSingnegativeelectrodes.AseriesofnoveltransitionmetalnitridesofC03N、Fe剁、N13NandMndNthinfilmshavebeensuccessfullyfabricatedbyusingreactivepulsedlaserdepositionandDCdischargemethodsinanitrogenam
4、bient.Thestructure,morphologyandcompositionoftheaS—depositedthinfiImswillbeinvestigated.The1ithiumelectrochemicolreactionofthinfiimswillbereportedinthisthesiS.1.CmNandFeaNthinfi1mshavebeensuccessfullypreparedby355nmpulsedlaserreactivedeposition.Theoptimumexperimentalcond
5、itionsforthepreparationofthinfilmarefoundtobeatthesubstratetemperatureof200。C,andambientnitrogengasof30Pa,thelaserenergydensityof4J/cma,theDCbiasof650Vandthedepositiontimeof2h。Thereversibledischargecapacitiesoftheas—depositedthinfiimsofC03NandFe洲rangefrom324mAh/gto420mAh
6、/g.Thestructure,morphologyandcompositionoftheas—deposited,1ithiatedanddelithiatedC03NandFe3NthinfiImshavebeencharacterizedbyX-raydiffraction(XRD),X-rayphotoelectronspectroscopy(XPS)andscanningelectronmicroscopyfSEM)。TheirelectrochemicalreactionwithLicannotbeexplainedbyth
7、eoxidation/reductionofnanosizedmetals.OnepartofmetallicCoandFearenitridedandreducedinthe1ithiumelectrochemicolreaction:theotherpartofCoandFeseemstoactasanactivespectatortohelpinIIAbstracttheformationanddecompositionofLi3N.2.Ni3NthinfiImshavebeensuccessfullypreparedby355n
8、mpulsedlaserreactiredepositionunderthesameexperimentaleonditionsasthefabricationofC03NandFejNthinfilms.
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