碳纳米材料讲稿.ppt

关于碳纳米材料第一页，讲稿共二十八页哦Fourpartsv1.Introductionv2.Experimentv3.Resultsanddiscussionv4.Conclusions第二页，讲稿共二十八页哦Introductionvtransitionmetaloxideshaveattractedgreatattentionasanodematerialsforlithiumionbatteries,dueto1theirhightheoreticalcapacity2safety3lowcost4naturalabundance第三页，讲稿共二十八页哦vSomeobstacle1poorcyclingperformance(largevolumeexpansionduetothegenerationofLi2O)2poorelectronicconductivity(electrodematerialswithdesignednanostructurecanimproveit)第四页，讲稿共二十八页哦vMnOshowsrelativelylowelectromotiveforce电动势(emf)value(1.032Vvs.Li+/Li)andhighdensity(5.43gcm3).However,thiskindofmaterialhasseldombeenreportedasananodematerialvnanocrystallineMnOthinfilm,andMnOpowderasanodehasshownlowoverpotential超电势andgoodcyclingperformance第五页，讲稿共二十八页哦vInthispaperThepreparedMnO/CcoreshellnanorodsmuchhigherspecificcapacitythanthatofMnOmicroparticlesandMnO2nanowiresasanodematerialoflithiumionbattery.返回第六页，讲稿共二十八页哦Experiment合成部分vMnO/CcoreshellnanorodsweresynthesizedbythereductionofcarbonprecursorcoatedMnO2nanowires.vTheMnO2nanowiresweresynthesizedbyatypicalhydrothermalreaction第七页，讲稿共二十八页哦Experiment表征vX-raydiffractionvFieldemissionscanningelectronmicroscopy(FESEM）vtransmissionelectronmicroscopy(TEM)vSAED第八页，讲稿共二十八页哦Experiment电化学实验部分vperformingusing2032coin-typecellsassembledinanargon-filledgloveboxvslurry:activematerials(70wt%),acetyleneblack乙炔黑(20wt%),andpolyvinylidenefluoride聚偏二氟乙烯(PVDF10wt%)inN-methyl-2-pyrrolidone氮甲基二吡咯烷酮(NMP).vTheslurrywasspreadontotheCufoilwithadoctorblade刮墨刀片anddriedat120Covernightundervacuum第九页，讲稿共二十八页哦Experimentvelectrodeareais1cm2vloadingofactivematerialis1.01.2mgcm2velectrolyte:asolutionof1MLiPF6inethylenecarbonate碳酸亚乙酯(EC)anddimethylcarbonate碳酸二甲酯(DMC)withaweightratioof1:1第十页，讲稿共二十八页哦ExperimentvPurelithiumfoilwasusedascounterandreferenceelectrodevCyclicvoltammetry循环伏安法(CV)vChargedischargetestingwasperformedintherangeof0.013.0Vvspecificcapacity返回第十一页，讲稿共二十八页哦Resultsanddiscussionv1、MnO2nanowiresweresynthesizedbyhydrothermalreaction.Thecrystalstructureoftheas-preparedMnO2nanowireswasconfirmedbyXRD(Fig.1)vAllthediffractionpeakscanbeindexedtothebody-centeredtetragonal-MnO2phase第十二页，讲稿共二十八页哦Resultsanddiscussionv2、MnO/CcoreshellnanorodswereobtainedthroughsinteringthecarbonprecursorcoatedMnO2nanowiresinflowingArcontaining5vol.%H2.AsshowninFig.1vthecrystalstructureofMnO/Ccoreshellnanorodscanbeindexedtotheface-centeredcubicphaseofMnOvlowintensitydiffractionpeakintherangeof2030islikelyassociatedwiththepresenceofamorphouscarbon无定形碳(originatedfromthedecompositionofthecopolymersurfactant).第十三页，讲稿共二十八页哦Resultsanddiscussion第十四页，讲稿共二十八页哦ResultsanddiscussionFESEM:nanowire structure with diameters ranging from 2050 nm and There is no significant change in diameter第十五页，讲稿共二十八页哦ResultsanddiscussionTEM第十六页，讲稿共二十八页哦Thenanorodsshowpolycrystallinefeatureandareagglomeratedintobundleswithalengthextendingtoafewhundrednanometers.ThefracturingofthenanowirestructureintonanorodsmaybecausedbythereductionfromMnO2toMnO.Anindividualnanorodconsistsofnanoparticleswithdiametersfrom20nmto30nm.Resultsanddiscussion第十七页，讲稿共二十八页哦ResultsanddiscussionAllthediffractionringscanbeindexedtotheface-centeredcubicFm-3mcrystalstructure.第十八页，讲稿共二十八页哦ResultsanddiscussionHRTEM第十九页，讲稿共二十八页哦ResultsanddiscussionvIntheregionA:thesurfaceoftheMnOcrystal,andthelatticecanbeclearlyresolvedwithad-spacingof0.255nmforthe(111)planes.vintheregionB:carbonlayer,whichpresentsnumerousblackspots,indicatingthatthesurfaceofthenanorodiscoveredwithathinlayerofamorphouscarbon.Ontheedgeofthenanorod,athincarbonlayerwithathicknessof12nmisclearlyvisible.第二十页，讲稿共二十八页哦Resultsanddiscussioncyclicvoltammetry(CV)第二十一页，讲稿共二十八页哦Resultsanddiscussion第二十二页，讲稿共二十八页哦Resultsanddiscussion第二十三页，讲稿共二十八页哦ResultsanddiscussionCyclingperformance第二十四页，讲稿共二十八页哦ResultsanddiscussionvThisnanorodelectrodeexhibitedhighercapacitythanthatofMnO2nanowireelectrodeafter40cycles.vThegoodelectrochemicalperformanceisaresultofthecombinedadvantagesofthenanorodstructureandtheporouscarboncoatinglayer.第二十五页，讲稿共二十八页哦ResultsanddiscussionvNanosizematerialswithlargesurfaceareacanprovidemoreactivesitesforLi+intercalation/de-intercalationandshortenthediffusionlengthforlithiumionsinthesolidphase.vThenanoporouscarboncoatinglayerwithmesoporescanformamixedconducting3DnetworkthatfacilitatesthemigrationofboththeLi+andthee,sothattheyreacheachsurfaceoftheMnOnanorods.返回第二十六页，讲稿共二十八页哦Conclusions1、UsingblockcopolymerF127asthecarbonsource,MnO/CcoreshellnanorodsweresuccessfullypreparedfromMnO2nanowiresbycalcinationinagasflowof5vol.%H2inAr.2、TheXRDpatternshowsthattheproducthasaface-centeredcubicphasestructure.FESEMandTEMimagesshowthatathincarbonlayerwascoatedonthesurfacesoftheMnOnanorods.第二十七页，讲稿共二十八页哦感感谢谢大大家家观观看看第二十八页，讲稿共二十八页哦