釩摻雜磷酸鐵鋰的合成和電化學性能研究.pdf

1、東南大學碩士學位論文釩摻雜磷酸鐵鋰的合成和電化學性能研究姓名：曲麗敏申請學位級別：碩士專業(yè)：化學；物理化學指導教師：雷立旭20120529AbstractAbstractRecently，lithiumironphosphate懿apositivematerialforLiionbatterieshasattractedmanyresearchersbecauseoftheirlowproducingcost，goodelectroch

2、emicalandthermalstabilities，safetlyHowever，theintrinsiclowelectronicconductivityofLiFeP04andslowtransferrateoflithiumionsseriouslyimpairitsrateperformanceVariousmathodsforthesynthesisincludingothermetaldopingandcarboncoa

3、tinghavebeenemployedtoimprovetheelectrochemicalperformancesofLiFeP04Inthisregard，wehaveinvestigatedtheeffectofthetemperature，carboncoatingandmetaliondopantsonthestructureandelectrochemicalperformanceofLiFeP04Moreoverweha

4、veemployedvanadiumionasthedopantsforLiFeP04andsynthesizedvanadiumdopedpositivematerialLiFel“P04／c@=001，005，01，02，03)，aswellasitselectrochemicalbehavioursandcyclingperformancesThedopingofvanadiumionanditseffectsonthestruc

5、ture，morphologyandelectrochemicalperformancesofLiFeP04havebeeninvestigatedbyXraydiffraction(XRD)，scanningelectronmicroscopy(SEM)，cyclicvoltammetry(CV)，electrochemicalimpedancespectroscopy(EIS)，galvanostaticchargedischarg

6、ecyclingXRDpatternsofLiFel吖VxP04／CsamplesshowedthattlleyaremixturesofLiFeP04andLi3V2(P04)3ElectrochemicalstudiesshowthatthedopingofcanadiumimprovesthecyclicstabilityandtherateperformanceofthepositivematerialForexample，th

7、eLiFeP04／Cmaterialwiththedopingof20％vanadiumexhibitsanexcellentperformanceItgivesaspecificdischargecapacityof1102mAh／gat05Cafter20cyclesandthecapacitykeepshigherthan70％ofitsmaximumattheratefrom01Cto30CFurthermore，PorousL

8、iFe08v02POdCmaterialshavebeensynthesizedbymechanicalsolidstatereactionTheyhavebetterinitialcharge—dischargeefficiencydischargerateandcycleperformancethanthosesynthesizedbyacoprecipitationmethodForexample，theinitialdischa