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1、关于碳纳米材料第1页,讲稿共28张,创作于星期二Fourpartsv1.Introductionv2.Experimentv3.Resultsanddiscussionv4.Conclusions第2页,讲稿共28张,创作于星期二Introductionvtransitionmetaloxideshaveattractedgreatattentionasanodematerialsforlithiumionbatteries,dueto1theirhightheoreticalcapacity2safety3lowcost4naturalabundance第3页,讲稿共28张,创作于星期二vS
2、omeobstacle1poorcyclingperformance(largevolumeexpansionduetothegenerationofLi2O)2poorelectronicconductivity(electrodematerialswithdesignednanostructurecanimproveit)第4页,讲稿共28张,创作于星期二vMnOshowsrelativelylowelectromotiveforce电动势(emf)value(1.032Vvs.Li+/Li)andhighdensity(5.43gcm3).However,thiskindofmateri
3、alhasseldombeenreportedasananodematerialvnanocrystallineMnOthinfilm,andMnOpowderasanodehasshownlowoverpotential超电势andgoodcyclingperformance第5页,讲稿共28张,创作于星期二vInthispaperThepreparedMnO/CcoreshellnanorodsmuchhigherspecificcapacitythanthatofMnOmicroparticlesandMnO2nanowiresasanodematerialoflithiumionbat
4、tery.返回第6页,讲稿共28张,创作于星期二Experiment合成部分vMnO/CcoreshellnanorodsweresynthesizedbythereductionofcarbonprecursorcoatedMnO2nanowires.vTheMnO2nanowiresweresynthesizedbyatypicalhydrothermalreaction第7页,讲稿共28张,创作于星期二Experiment表征vX-raydiffractionvFieldemissionscanningelectronmicroscopy(FESEM)vtransmissionelect
5、ronmicroscopy(TEM)vSAED第8页,讲稿共28张,创作于星期二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).vTheslurrywasspreadontotheCufoilwithadoc
6、torblade刮墨刀片anddriedat120Covernightundervacuum第9页,讲稿共28张,创作于星期二Experimentvelectrodeareais1cm2vloadingofactivematerialis1.01.2mgcm2velectrolyte:asolutionof1MLiPF6inethylenecarbonate碳酸亚乙酯(EC)anddimethylcarbonate碳酸二甲酯(DMC)withaweightratioof1:1第10页,讲稿共28张,创作于星期二ExperimentvPurelithiumfoilwasusedascounter
7、andreferenceelectrodevCyclicvoltammetry循环伏安法(CV)vChargedischargetestingwasperformedintherangeof0.013.0Vvspecificcapacity返回第11页,讲稿共28张,创作于星期二Resultsanddiscussionv1、MnO2nanowiresweresynthesizedbyhydrothermalreaction.Thecrystalstructureoftheas-preparedMnO2nanowireswasconfirmedbyXRD(Fig.1)vAllthediffrac
8、tionpeakscanbeindexedtothebody-centeredtetragonal-MnO2phase第12页,讲稿共28张,创作于星期二Resultsanddiscussionv2、MnO/CcoreshellnanorodswereobtainedthroughsinteringthecarbonprecursorcoatedMnO2nanowiresinflowingArcontaining5vol.%H2.AsshowninFig.1vthecrystalstructureofMnO/Ccoreshellnanorodscanbeindexedtotheface-cen
9、teredcubicphaseofMnOvlowintensitydiffractionpeakintherangeof2030islikelyassociatedwiththepresenceofamorphouscarbon无定形碳(originatedfromthedecompositionofthecopolymersurfactant).第13页,讲稿共28张,创作于星期二Resultsanddiscussion第14页,讲稿共28张,创作于星期二ResultsanddiscussionFESEM:nanowire structure with diameters ranging f
10、rom 2050 nm and There is no significant change in diameter第15页,讲稿共28张,创作于星期二ResultsanddiscussionTEM第16页,讲稿共28张,创作于星期二Thenanorodsshowpolycrystallinefeatureandareagglomeratedintobundleswithalengthextendingtoafewhundrednanometers.Thefracturingofthenanowirestructureintonanorodsmaybecausedbythereductionf
11、romMnO2toMnO.Anindividualnanorodconsistsofnanoparticleswithdiametersfrom20nmto30nm.Resultsanddiscussion第17页,讲稿共28张,创作于星期二ResultsanddiscussionAllthediffractionringscanbeindexedtotheface-centeredcubicFm-3mcrystalstructure.第18页,讲稿共28张,创作于星期二ResultsanddiscussionHRTEM第19页,讲稿共28张,创作于星期二Resultsanddiscussio
12、nvIntheregionA:thesurfaceoftheMnOcrystal,andthelatticecanbeclearlyresolvedwithad-spacingof0.255nmforthe(111)planes.vintheregionB:carbonlayer,whichpresentsnumerousblackspots,indicatingthatthesurfaceofthenanorodiscoveredwithathinlayerofamorphouscarbon.Ontheedgeofthenanorod,athincarbonlayerwithathickne
13、ssof12nmisclearlyvisible.第20页,讲稿共28张,创作于星期二Resultsanddiscussioncyclicvoltammetry(CV)第21页,讲稿共28张,创作于星期二Resultsanddiscussion第22页,讲稿共28张,创作于星期二Resultsanddiscussion第23页,讲稿共28张,创作于星期二ResultsanddiscussionCyclingperformance第24页,讲稿共28张,创作于星期二ResultsanddiscussionvThisnanorodelectrodeexhibitedhighercapacityth
14、anthatofMnO2nanowireelectrodeafter40cycles.vThegoodelectrochemicalperformanceisaresultofthecombinedadvantagesofthenanorodstructureandtheporouscarboncoatinglayer.第25页,讲稿共28张,创作于星期二ResultsanddiscussionvNanosizematerialswithlargesurfaceareacanprovidemoreactivesitesforLi+intercalation/de-intercalationan
15、dshortenthediffusionlengthforlithiumionsinthesolidphase.vThenanoporouscarboncoatinglayerwithmesoporescanformamixedconducting3DnetworkthatfacilitatesthemigrationofboththeLi+andthee,sothattheyreacheachsurfaceoftheMnOnanorods.返回第26页,讲稿共28张,创作于星期二Conclusions1、UsingblockcopolymerF127asthecarbonsource,MnO/CcoreshellnanorodsweresuccessfullypreparedfromMnO2nanowiresbycalcinationinagasflowof5vol.%H2inAr.2、TheXRDpatternshowsthattheproducthasaface-centeredcubicphasestructure.FESEMandTEMimagesshowthatathincarbonlayerwascoatedonthesurfacesoftheMnOnanorods.第27页,讲稿共28张,创作于星期二感谢大家观看第28页,讲稿共28张,创作于星期二
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