硅负极材料的相关应用介绍.pptx
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硅负极材料的相关应用介绍.pptx
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寿命寿命硅负采材料Siliconanodewithlifecyclelife,Prof.XinpingQiuDepartmentofChemistry,TsinghuaUniversityBeijing,100084,China,11/8/2023,Si:
4200mAh/g,1,Multielectronreactionmaterials,11/8/2023,J.R.Dahn,Electrochem.Solid-StateLett.,2001,4,A137.J.R.Dahn,J.Electrochem.Soc.2003,150,A1457.,2,Colossalvolumechange,Changein(a)length+andwidthx,(b)height,and(c)volumeofthea-Sitowercomparedto(d)voltagevs.AFMscannumber.,SchematicdiagramoftheinsituAFMapparatus.,OpticalmicrographofaLi-alloyfilmafterexpansion,11/8/2023,Y.Cui,Nat.Nanotechnol.,2008,3,31.|Y.Cui,NanoLett.2011,11,2949.|G.Yushin,Nat.Mater.,2010,9,353.|G.A.Ozin,Adv.Funct.Mater.2009,19,1999.|X.J.Huang,Adv.Mater.2011,23,4938.|X.P.Qiu,Electrochem.Commun.,2007,5,930.|S.M.Lee,Electrochim.Acta,2008,53,4500.|J.G.Zhang,J.Electrochem.Soc.,2010,7,A765.|J.R.Dahn,Electrochem.Solid-StateLett.,2007,10,A17.|G.Yushin,ACSAppl.Mater.Inter.,2010,11,3004.|G.Yushin,Science,2011,334,75.,3,Strategiesforsiliconanodes,Particlepulverization,“Astrongsizedependenceoffractureinsiliconmaterialwasdiscoveredthatthereexistsacriticalparticlesizeof150nmbelowwhichcrackingdidnotoccur.”2,Sizeeffect,1HZhang,NanoLetters2012,12,2778.;2XHLiu,ACSNano.2012,2,15221531,11/8/2023,4,Currentcollector;Binder;Array,StabilityinSi-basedmaterial,?
1,11/8/2023,5,TheexposedactivesurfaceduetothevolumechangecausecontinualformationofSEIfilmsandlowcoulombicefficiency(CE).,Researchroutes,ReducetheparticlesizetoaccommodateSEIfilmDesignporousorhollowstructuretobufferthevolumeexpansionCompositewithCorMetal(Cu)toincreaseelectronicconductivityandmodifytheinterfacebetweenSiandelectrolyte.InvestigatenewbinderandelectrolyteadditivessystemforSi-basedanodematerials,StabilityofSEIfilm,6,11/8/2023,PorousSi/Ccomposite,SynthesisProcess,11/8/2023,Morphology,7,in1bold,1ePorousstructureofcarbonsubstratecanbeobservedfromTEMimagesAfterCVD,siliconparticlesadheretotheframeworkandporousstructurewasmaintained.Particlesizeofsiliconis10nmandhomogeneouslydispersed.ThedepositedsiliconinPorousSi-Cisamorphous,asindicatedbytheabsenceofcrystallitesandbroaddiffuseringsintheSAEDpatterns.Incontrast,whencompositeisheatedto700Cfor0.5h,alatticefringecorrespondingtod111=0.31nmforsiliconisseeninPorousSi-C-700.,Resultsandanalysis,SEMandTEMimages,11/8/2023,8,in1bold,1eObviouscharacteristicpeakofcrystalsiliconafterheattreatmentat700Cfor0.5hThreeobviousdiffractionpeaksaround28,47and56arefoundafterheattreatment,whichcorrespondverywelltothe(111),(220)and(311)peaksofsiliconwithoutanyimpuritypeaks.Thepeakat520cm-1(indicativeofcrystallinesilicon)isnotdetectedaftersiliconCVD.Thebandscenteredaround155,474cm-1andtheweakshoulderat400cm-1aretypicalfeaturesofamorphoussiliconvibrationmodes1.,Resultsandanalysis,Structuralcharacterization,1D.Aurbach,J.Phys.Chem.C,2007,111,11437.,XRDpatternsandRamanspectra,N2sorptionisotherms,Poresizedistribution,BothporouscarbonandporousSi-CshowtypeIVisotherm,whichistypicalcharacteristicofmesoporousstructureObviousdecreaseofspecificsurfacearea(SSA)andporevolumeafterSiCVD,Porouscarbon:
650m2/g,1.32cc/g,PorousSi-C:
150m2/g,0.39cc/g,Poreswithdiameterof3nmgeneratedbydecompositionofsucrosePoreswithdiameterof1040nmduetotheremovalofCaCO3template,whichwerereducedafterSiCVD,PorousStructure,11/8/2023,9,Charge-Dischargecurves,Cyclingperformance,1)2ndchargecapacity;2)VC:
vinylenecarbonate,11/8/2023,10,Electrochemicalperformance,1stdchcapacity:
2404mAh/g1stchcapacity:
1541mAh/g1stcoulombicefficiency:
64.1%Reversiblecapacity1:
1504mAh/gCapacityretention:
67%after200cycles,Recipe:
PorousSi-C:
CB:
binder(PAA)=6:
2:
2;Electrolyte:
1MLiPF6inEC-DMC-EMC(1:
1:
1vol%)with2wt%VC2;loading:
0.61mg/cm2.Capacityisonlybasedonactivematerial.Currentdensity:
0.1A/gfor1-2cycle,then0.5A/g;Voltage:
0.052.0Vvs.Li,Ratecapability,Increasecurrentdensityfrom0.1to2Ag-1,thespecificcapacityofSi/Ccompositeisstillabove500mAhg-1,whenthecurrentdensitychangesbackto0.1Ag-1,morethan92%ofthecapacityatthefirsttencyclesisrecoverable.,11/8/2023,11,Resultsandanalysis,NyquistplotofSi-Ccompositeattheendofdischargeafterdifferentcycles,in1bold,1eElectrochemicalimpedancespectra(EIS)measurementina5.0mVACvoltagesignalinthe105-0.02Hzfrequencyrange.BeforeeachEIStest,theelectrodesweredischargedto0.01Vgalvanostaticallyandthenremainedatopen-circuitforatleast2htostabilizetheirpotential.Theconstancyofthecharacteristicfrequency(20Hz,from30-60cycles)suggeststhatthekineticsofthechargetransferreactiondoesnotvaryuponcycling.Evolutionoftheresistanceinmid-frequencyregion(inset)showsanincreaseinfirst5cyclesthenreduceandmaintainaround40Ohminlatercycles.,Resultsandanalysis,11/8/2023,12,EIStest,1D.Guyomard,J.Mater.Chem.,2011,21,6201.,SEIfilmwithcycling,Superficialandcross-sectionalSEMimagesofourcompositeaftera),b)10cycles;c),d)20cycles;e),f)50cyclesandg),h)commercialSimaterialafter50cycles.,PorousstructureofoursynthesizedcompositestillmaintainsaftercyclingandSEIfilmisonlyobservedattheexternalsurfaceofthesiliconparticlewithoutobviousincrassation.IncommercialSimeasurements,excessiveSEIfilmisfoundafter50cycles,whichisunabletobedistinguishedfromSinanoparticles.,11/8/2023,13,Materialsaftercycling,1Y.Cui,NanoLett.10(2010)1409,Si/Cafter50cycles,a)SEMandb)TEMimageofSi/Ccompositeattheendof50thcycle;thecorrespondingelementalmappingofc)carbonandd)silicon.1mMofaceticacidwasusedtoremovetheSEIfilm1.Porouscarbonstructureismaintained,nanosiliconparticlesaround10nmdoesnotshowaggregationandrupture.,Resultsandanalysis,a),b),c),d),C-K,Si-K,11/8/2023,14,SEIconfinement,Schematic,11/8/2023,15,SEIfilmformsinsidetheporesduetothelowelectrochemicalpotentialoflithiuminsertioninfirstfewcycles.Whentheporesarefullfilled,SEIfilmisconfinedbythewallofcarbonsubstrate,whichpreventtheinternalsiliconparticlefrombeingexposedintheelectrolyte.,Results,11/8/2023,16,Schematicofsynthesis,Advantage:
1.EasytosynthesisandregulateaccordingtocommercialCaCO3template2.Hollowstructurewithreservevolumecanaccommodatelargevolumechanges3.Interconnectednanosiliconmeansmoreactiveconductivecontact.,Hollowsilicon,11/8/2023,17,Imagesandpatterns,Morphology,Results,a)TEMimagesofnanoCaCO3template;b)SEMimagesofHSA-10(insetisatlowmagnification);TEMimagesofc)HSA-10,e)HSA-15,f)HSA-20;d)thecorrespondingSAEDpatternofHSA-10.Amorphoushollowsiliconmaterialwithdifferentshellthicknesswasprepared,11/8/2023,18,Imagesandpatterns,Structuralcharacterization,b,c,Characteristicpeaksofcrystallinesilicon(PDF#65-1060)around28,47and56areabsent,whichcorroboratethestatementofsiliconisamorphous.Thefirstmain3/2-1/2doublet(thespin-orbitsplittingis0.6eVandtheintensityratiois3:
1),locatedat99.1-99.7eVcorrespondstoSi0(75%content).Thecomponentlocatedathigherbindingenergy(100.0eV)isassociatedwithSiOxformedatthesurfaceofHSAwithaproportionof25%.,Resultsandanalysis,11/8/2023,19,Resultsandanalysis,Thenitrogenadsorption/desorptionisothermsofHSAsamplesshowasharpcapillarycondensationstepathighrelativepressures(P/P0=0.85-0.99),indicatingtheexistenceoflargepores.Correspondingporesizedistributesmainlyintherangeof20nmand100nm,whichisattributedtotheremovalofsite-occupyingnanoCaCO3.,IsothermandPoresizedistribution,PorousStructure,11/8/2023,20,Cyclingperformance,Cycleperformance,TestconditionsRecipe:
HS:
CB:
binder(PAA)=6:
2:
2Electrolyte:
1MLiPF6inEC-DMC-EMC(1:
1:
1vol%)with2wt%VC;Loading:
0.4-0.6mgcm-2Currentdensity:
0.1A/gfor1-3cycle,then0.4A/g;Voltage:
0.021.50Vvs.LiResultsHSA-10givesthehighestcapacityretention(91%)in100cyclesandcorrespondingreversiblecapacityis980mAhg-1.Whenincreasetheshellthicknessofsilicon,reversiblecapacityincreases(980mAhg-1ofHSA-15and1133mAhg-1ofHSA-20after100cycles)butthecapacityretentiondecreasesobviously(76%ofHSA-15and73%ofHSA-20),Electrochemicalperformance,Materialsaftercycling,1Y.Cui,NanoLett.10(2010)1409,HAS-10after50cycles,a)SEMimageofHSA-10after100cycles;b)SEMimageofHSA-10after100cycleswithoutSEIfilm;c),d)TEMimageofHSA-10after100cycleswithoutSEIfilmatdifferentmagnification.Aggregatedsecondaryparticles(Fig.c)and10nmsiliconshellstructure(Fig.b&d)weremaintainedwithoutfractureofthehollowspheres.,Resultsandanalysis,11/8/2023,21,a,b,c,d,EIStest,11/8/2023,22,Stableinterfaceandsmallerresistance,NyquistplotofSi-Ccompositeattheendofdischargeafterdifferentcycles,in1bold,1eElectrochemicalimpedancespectra(EIS)measurementina5.0mVACvoltagesignalinthe105-0.02Hzfrequencyrange.BeforeeachEIStest,theelectrodesweredischargedto0.01Vgalvanostaticallyandthenremainedatopen-circuitforatleast2htostabilizetheirpotential.Evolutionoftheresistanceinmid-frequencyregionmaintains20OhmduringcyclingwhichislowerthanSi/CcompositeandnanoSimaterial.,Resultsandanalysis,DSCTest,11/8/2023,23,StableSEIstructureofsiliconfoam,DSCheatingcurves,in1bold,1eCurrentdensityaround0.1mA/gwasappliedtolithiatetheSiactivematerial.Afterthevoltagereached1mV,thecellswereremainedatopen-circuitfor2hthencarefullyopenedinaglovebox.TheelectrodewassoakedinDMCandthendriedundervacuumovernight.MeasurementswereconductedwithaDSC1(METTLERTOLEDO)atatemperatureramp
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