天津理工大学-张联齐(梯度三元材料)

Core-shellstructuredLiNixCoyMn1-x-yO2cathodematerialsforLi-ionbatteryLianqiZhang1,PeiyuHou1,EnlouZhou1,DaweiSong1,XixiShi1,XiaoqingWang2,JunZhang3,JianGuo31TianjinUniversityofTechnology,Tianjin300384,China2TianjinPolytechnicUniversity,Tianjin300387,China3PylonTechnologiesCo.,Shanghai201203,China天津理工大学April8-10,2013ContentBackground1Designofcore-shellstructure2Synthesisandcharacterization3Summary4AdvancedMaterialsGroupforGreenBatteries1.ResearchBackgroundCore-shellstructure具有双层或多层结构，其内部和外部分别富集不同成分，使得核与壳的功能实现复合与互补，从而可以调制出有别于核或壳本身性能的新型功能材料。AdvancedMaterialsGroupforGreenBatteries锂电池正极核壳材料研究进展Y.K.SunandK.Amineetal.,J.Am.Chem.Soc.,2005,127,13411-13418.Theprogressoncore-shelllayeredmaterialsforLi-ionbatteryI.Simplecore-shellstructureAdvancedMaterialsGroupforGreenBatteriesY.K.SunandK.Amineetal.,Nat.Mater.,2009,8,320-324.II.Concentrationgradientcore-shellstructureAdvancedMaterialsGroupforGreenBatteries(a)(b)ContourplotsofinsituHEXRDprofile.(a),DelithiatedICmaterial.(b),DelithiatedFCGmaterialduringthermalrampingY.K.Sun,Z.H.Chen,H.J.Noh,D.J.Leeetal,Nat.Mater.,2012,12,942-947.III.Fullconcentrationgradientcore-shellstructureAdvancedMaterialsGroupforGreenBatteriesTheobservedadvantagesofcore-shelllayeredcathodeandtheremainingproblemsTheremainingproblem:Thesignificantlyimprovedcomprehensiveperformancessuchascycleabilityandthermalstabilityincontrasttocoreorshellmaterials.Theobservedmerits1)needingscientificcomparison:Theimprovementsmaycomefromthevariationofchemicalcompositionduetosignificantdifferenceincompositionsbetweencore-shellmaterialsandcoreorshellmaterials;2)Effectsofsinteringtemperature;3)NodatasupportingthatCGorFCGarebetter.2.Designofcore-shellstructureDesigningcore-shellstructuredNCM111,NCM523andNCM712withtheaidofatrianglediagramofLiCoO2-LiNiO2-LiMnO2Li[Ni0.5Co0.2Mn0.3]O2(NCM523)Li[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2]O2coreshell1shell2coreshellLi[(Ni0.6Co0.2Mn0.2)1/2(Ni0.4Co0.2Mn0.4)1/2]O2DoubleshelledNCM523SingleshelledNCM523coreLi[Ni1/3Co1/3Mn1/3]O2(NCM111)coreshellcoreshellx+2y-2xy=2/3(0x2/3)Suchasx=0.2andthenLi[Co5/12Ni7/24Mn7/24]0.8[Ni1/2Mn1/2]0.2O2Li{[NiyMnyCo1-2y](1-x)}core{[Ni1/2Mn1/2]x}shellO2(0x2/3)=LiNi1/3Mn1/3Co1/3O211Li[Ni0.7Co0.1Mn0.2]O2(NCM712)coreshellLi[(Ni0.8Co0.1Mn0.1)0.7(Ni0.4Co0.2Mn0.4)0.3]O2SingleshelledNCM712Li[(Ni0.8Co0.1Mn0.1)0.7(Ni0.4Co0.2Mn0.4)0.3]O2Li{[NiyMnyCo1-2y](1-x)}core{[Ni1/2Mn1/2]x}shellO2Li[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2]O2Core-shell3.SynthesisandcharacterizationofmaterialsSyntheticprocessInstrument（a）core；（b）first-shelled;（c）doubleshelled；（d）non-core-shelledEDS（c）[Ni0.379Co0.213Mn0.408](OH)2（d）[Ni0.481Co0.207Mn0.311](OH)23.1DoubleshelledNCM5233.1.1Precursors0.1110100051015202530DifferentialDistribution/%Diameter/μm[Ni0.8Co0.1Mn0.1](OH)2[(Ni0.8Co0.1Mn0.1)4/7(Ni1/3Co1/3Mn1/3)3/7](OH)2[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2](OH)2ThechangeofparticlesizefordoubleshelledNCM523precursorsD50dataforcore,first-shelledanddouble-shelledprecursorsare5.93μm,7.35μmand8.63μmduringcontinuousprecipitation，respectively,suggestingformationofcore-shellstructureincombinationofEDSdata.1020304050607080210110116113018107105104102006101003Intensity/A.U.2Theta/°(a)-Li[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2]O2(b)-Li[Ni0.5Co0.2Mn0.3]O2(a=2.8759,c=14.2619)(a=2.8732,c=14.2501)(a)(a)(a)(b)EDSsupportformationofcore-shellstructure;ItisdifficulttofindsignificantdifferencefromXRD.（a）core-shell(b)non-core-shell3.1.2Comparisonbetweencore-shelledandnon-core-shelledNCM523EDS（a）------------------------------（d）Li[Ni0.416Co0.202Mn0.382]O2AdvancedMaterialsGroupforGreenBatteries50100150200250300350Heatflow/wg-1Temperature/°CLi[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.)1/2]2Li[Ni0.5Co0.2Mn0.3]O2Chargedto4.3V050100150100150200Li[(Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2]O2Li[Ni0.5Co0.2Mn0.3]O2Dischargecapacity/mAhg-1Cycle/nThedoubleshelledNCM523hasremarkablebettercycleabilityandthermalstabilitythannon-core-shellstructuredone.However,thetapdensityofmaterials(about1.9gcm-3)istoolowtobeingsuitabletoapplication.Therefore,syntheticoptimizationwascarriedout.CyclingperformancesDSCdata3.1.3.1DoubleshelledprecursorsCoreprecursorsOneshelledprecursorsDoubleshelledprecursorsEDS[Ni0.796Co0.103Mn0.101](OH)2[Ni0.392Co0.206Mn0.402](OH)2Additionally，ICPdataindicatethatthedoubleshelledandnon-core-shelledNCM523havechemicalcompositionsof[Ni0.507Co0.198Mn0.298](OH)2and[Ni0.503Co0.199Mn0.298](OH)2，respectively,showingquiteconsistentwiththedesigned[Ni0.5Co0.2Mn0.3](OH)2.(a)(c)(b)[Ni0.593Co0.193Mn0.204](OH)23.1.3SyntheticallyoptimizedNCM523precursorsNCM523Non-core-shellCore-shellNon-core-shellCore-shellBeforeoptimization1.37gcm-31.26gcm-31.93gcm-31.87gcm-3Afteroptimization2.09gcm-32.11gcm-32.59gcm-32.60gcm-3102030405060Intensity/A.U.2Theta/°[Ni0.8Co0.1Mn0.1](OH)2[Ni1/3Co1/3Mn1/3](OH)2[Ni0.4Co0.2Mn0.4](OH)2Ni0.8Co0.1Mn0.1)2/7(Ni1/3Co1/3Mn1/3)3/14(Ni0.4Co0.2Mn0.4)1/2](OH)20.111010005101520253035Di