碳纳米材料.ppt

关于碳纳米材料现在学习的是第1页，共28页Fourpartsv1.Introductionv2.Experimentv3.Resultsanddiscussionv4.Conclusions现在学习的是第2页，共28页Introductionvtransitionmetaloxideshaveattractedgreatattentionasanodematerialsforlithiumionbatteries,dueto1theirhightheoreticalcapacity2safety3lowcost4naturalabundance现在学习的是第3页，共28页vSomeobstacle1poorcyclingperformance(largevolumeexpansionduetothegenerationofLi2O)2poorelectronicconductivity(electrodematerialswithdesignednanostructurecanimproveit)现在学习的是第4页，共28页vMnOshowsrelativelylowelectromotiveforce电动势(emf)value(1.032Vvs.Li+/Li)andhighdensity(5.43gcm3).However,thiskindofmaterialhasseldombeenreportedasananodematerialvnanocrystallineMnOthinfilm,andMnOpowderasanodehasshownlowoverpotential超电势andgoodcyclingperformance现在学习的是第5页，共28页vInthispaperThepreparedMnO/CcoreshellnanorodsmuchhigherspecificcapacitythanthatofMnOmicroparticlesandMnO2nanowiresasanodematerialoflithiumionbattery.返回现在学习的是第6页，共28页Experiment合成部分vMnO/CcoreshellnanorodsweresynthesizedbythereductionofcarbonprecursorcoatedMnO2nanowires.vTheMnO2nanowiresweresynthesizedbyatypicalhydrothermalreaction现在学习的是第7页，共28页Experiment表征vX-raydiffractionvFieldemissionscanningelectronmicroscopy(FESEM）vtransmissionelectronmicroscopy(TEM)vSAED现在学习的是第8页，共28页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现在学习的是第9页，共28页Experimentvelectrodeareais1cm2vloadingofactivematerialis1.01.2mgcm2velectrolyte:asolutionof1MLiPF6inethylenecarbonate碳酸亚乙酯(EC)anddimethylcarbonate碳酸二甲酯(DMC)withaweightratioof1:1现在学习的是第10页，共28页ExperimentvPurelithiumfoilwasusedascounterandreferenceelectrodevCyclicvoltammetry循环伏安法(CV)vChargedischargetestingwasperformedintherangeof0.013.0Vvspecificcapacity返回现在学习的是第11页，共28页Resultsanddiscussionv1、MnO2nanowiresweresynthesizedbyhydrothermalreaction.Thecrystalstructureoftheas-preparedMnO2nanowireswasconfirmedbyXRD(Fig.1)vAllthediffractionpeakscanbeindexedtothebody-centeredtetragonal-MnO2phase现在学习的是第12页，共28页Resultsanddiscussionv2、MnO/CcoreshellnanorodswereobtainedthroughsinteringthecarbonprecursorcoatedMnO2nanowiresinflowingArcontaining5vol.%H2.AsshowninFig.1vthecrystalstructureofMnO/Ccoreshellnanorodscanbeindexedtotheface-centeredcubicphaseofMnOvlowintensitydiffractionpeakintherangeof2030islikelyassociatedwiththepresenceofamorphouscarbon无定形碳(originatedfromthedecompositionofthecopolymersurfactant).现在学习的是第13页，共28页Resultsanddiscussion现在学习的是第14页，共28页ResultsanddiscussionFESEM:nanowire structure with diameters ranging from 2050 nm and There is no significant change in diameter现在学习的是第15页，共28页ResultsanddiscussionTEM现在学习的是第16页，共28页Thenanorodsshowpolycrystallinefeatureandareagglomeratedintobundleswithalengthextendingtoafewhundrednanometers.ThefracturingofthenanowirestructureintonanorodsmaybecausedbythereductionfromMnO2toMnO.Anindividualnanorodconsistsofnanoparticleswithdiametersfrom20nmto30nm.Resultsanddiscussion现在学习的是第17页，共28页ResultsanddiscussionAllthediffractionringscanbeindexedtotheface-centeredcubicFm-3mcrystalstructure.现在学习的是第18页，共28页ResultsanddiscussionHRTEM现在学习的是第19页，共28页ResultsanddiscussionvIntheregionA:thesurfaceoftheMnOcrystal,andthelatticecanbeclearlyresolvedwithad-spacingof0.255nmforthe(111)planes.vintheregionB:carbonlayer,whichpresentsnumerousblackspots,indicatingthatthesurfaceofthenanorodiscoveredwithathinlayerofamorphouscarbon.Ontheedgeofthenanorod,athincarbonlayerwithathicknessof12nmisclearlyvisible.现在学习的是第20页，共28页Resultsanddiscussioncyclicvoltammetry(CV)现在学习的是第21页，共28页Resultsanddiscussion现在学习的是第22页，共28页Resultsanddiscussion现在学习的是第23页，共28页ResultsanddiscussionCyclingperformance现在学习的是第24页，共28页ResultsanddiscussionvThisnanorodelectrodeexhibitedhighercapacitythanthatofMnO2nanowireelectrodeafter40cycles.vThegoodelectrochemicalperformanceisaresultofthecombinedadvantagesofthenanorodstructureandtheporouscarboncoatinglayer.现在学习的是第25页，共28页ResultsanddiscussionvNanosizematerialswithlargesurfaceareacanprovidemoreactivesitesforLi+intercalation/de-intercalationandshortenthediffusionlengthforlithiumionsinthesolidphase.vThenanoporouscarboncoatinglayerwithmesoporescanformamixedconducting3DnetworkthatfacilitatesthemigrationofboththeLi+andthee,sothattheyreacheachsurfaceoftheMnOnanorods.返回现在学习的是第26页，共28页Conclusions1、UsingblockcopolymerF127asthecarbonsource,MnO/CcoreshellnanorodsweresuccessfullypreparedfromMnO2nanowiresbycalcinationinagasflowof5vol.%H2inAr.2、TheXRDpatternshowsthattheproducthasaface-centeredcubicphasestructure.FESEMandTEMimagesshowthatathincarbonlayerwascoatedonthesurfacesoftheMnOnanorods.现在学习的是第27页，共28页感感谢谢大大家家观观看看现在学习的是第28页，共28页