将无烟煤(ANT)的浮选精矿进行不同最高热处理温度(HTTma、)的热处理, 用密度和XRD图谱来表征热处理后ANT试样的微观结构。用恒电流充、放电实 验和粉末微电极循环伏安实验来检测上述ANT试样用作铿离子电池负极材料时 的充、放电性能。在此基础上探讨了ANT试样的微观结构与充、放电性能之间 的关系。考察了具有最佳贮铿结构的A30。。试样和六种电解液之间的相容性,利用 FTIR一图谱对A3000试样在上述六种电解液中首次充电时在炭负极表面所形成的 邻IC胃标电解质中间相)膜的成分和织构进行了分析,研究了试样和电解液的相 容性与SEI膜的关系。结合恒电流充、放电实验,采用正交法分析了充、放电电 流密度、A30。。试样的粒度、炭膜中乙炔黑的含量和PTFE的含量对A300。试样的 充、放电性能的影响。试验结果表明: 1 . HTTma、对ANT试样的微观结构和充、放电性能有很大影响。在HTTlnax< 2100℃的范围内,ANT试样属于乱层结构,石墨微晶尚未出现或数量很少,贮铿 机制为“孔隙贮铿”,由于孔隙的大小不一,插铿时克服阻力所需的电位也不同, 因此充、放电曲线呈“V”字形,无平稳的充、放电电位平台;随着HTTmax的增 大,试样中孔隙逐渐变小、变少,充、放电容量也逐渐变小。HTTma、二2100℃时, 微孔几乎消失,而石墨微晶又少又小,因此试样的充、放电容量最低。HTTInax> 2100℃时,石墨微晶迅速成长,充、放电容量迅速增大,充、放电曲线为“U” 字形,充、放电平台低而平稳,表现出典型的“石墨微晶层间嵌理”机制。与其 他软炭材料相比,ANT试样在进行热处理时,所需HTTma、高(最佳HTTmax=3000 ℃),高温段所需时间长,较难石墨化。 2 . 电解液组成对A300。试样的充、放电性能有明显的影响。A3oo。试样在六种 不同的电解液中,首次充电过程中所形成的SEI膜,其化学组分均为碳酸铿和烷 基碳酸铿,但在EC基电解液中形成的SEI膜薄而致密,可以有效地阻止溶剂化 铿离子插入石墨层间,不可逆容量少,表现出与A300。试样有良好的相容性;在PC 基电解液中形成的SEI膜厚,且有缺陷,不能有效地阻止溶剂化铿离子嵌入试样 中石墨微晶的层间,不可逆容量大,与A30。。试样的相容性极差。当采用EC基溶 剂体系时,以LIClq作溶质时的充、放电效率比以LIPF6作溶质时相对要高。 3 . 充、放电电流密度(A)、A30。。试样的粒度(B)、炭膜中导电剂乙炔黑的含 量(C)和粘结剂PTFE的含量(D)等因素对Ao00试样在1mol/LLICIO4/EC十DEC(1:l)电解液中的充、放电性能均有影响,但程度不同,对第三循环放电容量影 响大小的顺序为:A>C>B>D:对第三循环充、放电效率影响大小的顺序为: A>C>D>B。正交实验结果表明:当充、放电电流密度较大(I=巧m刀g)时, 可选取组合A,BZCZDZ,即A30。。试样粒度为一325目,炭膜中乙炔黑的含量为3%, PTFE含量为5%,其第三循环放电容量和效率分别为D3二305.8mAh/g、币二91.4%, 而当充、放电电流密度较小(I二lomA/g)时,可选取组合AZBZC3DI,即A3。。。试 样粒度为一325目,炭膜中乙炔黑的含量为5%,PTFE含量为3%,其第三循环放 电容量和效率分别为D3月13.smAh/g、币二91.7%。 4 . 粉末微电极快扫描循环伏安实验证明A30o。试样循环性能好,寿命长。当循 环到500周期时,氧化峰的面积约占最大氧化峰面积的70%以上。以氧化峰和还 原峰面积之比来估算第500个循环的充、放电效率,可知其充、放电效率超过 92 . 7%。 J卜 协 关键词:铿离子电池(LIB):炭负极材料:无烟煤;最高热处理温度: 与电解液的相容性Abstn玲t Thefloatationeoneentrateofanthracite(ANT)washeat一treatedwithdifferent maximumheattreatmenitemperature(HTTmax).ThemierostrueturesofthesamPles heat一treatedwithdifferentHTTma、wereeharacterizedbytheirdensitiesandXRD sPectra.Thecharging一dischargingPerformancesofthesesamPlesusedasthenegative eleetrodesinlithiumionbatteries(LIB)wereinvestigatedbygalvanostatie eharging一dischargingexperimentsandPowdermieroeleetrodeeyelicvoltammetry experiments.Therelationsbetweentheircharging一disehargingperformaneesandtheir microstruetureswerediseussed.TheeomPatibilitiesofsamPleA300owithsixkindsof eleetrolyteswereinvestigatedtoo.ThecomPositionsofthesolidelectrolyte inierphase(SEI)filmsformedduringthefirstchargingProeesswereanalyzedbyFT讯 sPectra.TherelationshiPbetweentheSEIfilmsandtheeomPatibilitiesofsamPles withelectrolyteswasexamined.Theinflueneesofotherfactors(the eharging一dischargingcurrentdensity,thegranularityofA;000,theeontentofaeetylene blackandthecontentofPTFE)onthecharging一disehargingPerformaneeofsamPle A;000werealsoinvestigatedbytheorthogonalmethodthroughgalvanostatie charging-discha几尹ngexperiments.Theexperimentalresultsareasfollows: 1 . Themierostrueturesandtheeharging一dischargingPerformaneesofANT samPlesrelatetoHTTmax.WhenHTTma、<2I000C,themierostructureoftheANT samPle15tuthostratic,thegraPhiteerystalliteshavenotaPPeared.Themeehanismof storinglithium一ions15toinsertlithiumionsintothemieroPoresofthesamPles.The charging一dischargingeurveslookliketheletter“V”andhavenoflatPlateausdueto thedifferentsizesofthemicroPores.InereasingtheHTTmax,themieroPoresinANT samPlesbecomefewerandsmaller,thereforethecharging一disehargingeaPacities deerease.WhenHTTma、=2100oC,theeharging一disehargingeaPaeityreaehesthe minimumsineethenumberofthemieroPoresreachestheminimumandthesizeof thembeeomeverysmall,thenumberofgraPhiteerystalliteinANTsamPles15stillfew andthesizeofthem15alsosmall.WhenHTTmax>2100oC,thegraPhiteerystallites growraPidl从andtheeharging一dischargingeaPacitiesofthesamPlesinerease,too.The meehanismofstoringlithium一ionsconvertstotheinterealationofthelithiumionsinto .人、 Ill 另thelayersofgraPhiteerystallites.Theeharging一disehargingeurvesofthesamPleslook liketheletter“U”andhavelowPoteniialflatPlateausParingwiththeothersoft earbonaceousmaterials,theHTTma、ofANTsamPle15higher(theoPtimtnnHTTma、15 3000℃)andthetimeofheatinginthehightemPeraturerange15long,itmeansthat theANTsamPlesaremoredi伍culttobegraPhitized. 2 . ThecomPositionsofeleotrolytesmakegreatinfiuencesonthe charging一disehargingPe而rmancesofANTsamPle.ThechemiealcomPositionsof SEIfilmsformedontheinte而eesofA3000samPlesindifferenteleetrolytesduringthe firstehargingProeessaremainlyLiZCO3andLIOCOZR,buttheirtexturesaredifferent. TheSEIfilmsformedinEC一basedeleetrolytesarethinandeomPaet,whiehean PreventthesolvatedlithitnnionsfromcoinierealatingbetweentwograPhenelayersof thegraPhiteerystalliteseffeetively,thereforesamPlesA300ohavesmallirreversible caPaeitiesandgoodeomPatibilitiesWiththiskindsofeleetrolytes.However’theSEI filmsformedinPC七asedeleetrolytesarethiekbutdefeetive,whicheouldnot effectivelyPreventsolvatedlithiumionsfrominterealation,thereforesamPleA300o showslargeirreversiblecaPaeitiesinPC一basedeleetrolytesandbadeomPatibilities withthiskindofelectrolytes.ForEC一basedsystem,thecharging一diseharging effieieneiesusingthesoluteLICIO;arealittlehigherthanusingthesoluteLIPF6. 3 . Otherfaetorssuehasthecharging一dischargingcurrentdensity(A),the granularityofA3。。。(B),theeonteniofaeetyleneblack(C)andthecontentofPTFE(D) alsomakeinfluencesonthecharging一disehargingPerformanceofsamPleA300。in differentdegrees,theorderarrangedaeeordingtothedegreeofinfluencingthe dischargingeaPaeitiesinthe3rdeycleD3inlmol/LLIC104甩C+DEC(l:l) eleetrolyteisA>C>B>Dandtheorderarrangedaecordingtothedegreeofinfluencing theeharging一dischargingemeienciesinthe3rdeyclen3isA>C>D>B.Theorthogonal experimentalresultsshowthatwhenthecharging一dischargingeurrentdensity15larger (I=15mA/g)andthesequeneeA,BZCZD:(i.e.thegranularityofsamPleA300o15一325 mesh,theeontentofacetyleneblaek153%andtheeontentofPTFE155%)was adoPted,theresultsareD3=305.smAh/gand月3=91.4%;whentheeharging一diseharging eurrentdensity15smaller(I=10mA/g)andthesequeneeAZBZC,DI(i.e.thegranularity ofsamPleA300o15一325mesh,theconientofaeetyleneblaek155%andthecontentof PTFE153%)wasadoPted,theresultsareD3=313.8mAh/gandn3二91.7%. 4.TheresultsofthefastseanningPowdermicroeleetrodeeyelicvoltammetry experimentsshowthatsamPleA;000hasagoodcyeliePe而rmaneeandalongcyclie :匀公 lV 么experimentsshowthatsamPleA300ohasagoodcyeliePerformaneeandalongeyelie ofthCareaofthelife.Inthe500theyeletheareaoftheoxidationpeak15about70%ofthear。 maximumoxidationpeakandtheeharging--disehargingeffieiencyofthe500th 92 . 7%,whichwasestimatedbytheratiooftheareaofoxidationpeaktothe reductionpeak. eycle15 盯eaof 耳 K叮words:lithium一ionbattery(LIB);earbonaceousnegativeeleetrodematerials; anthracite;themaximumheat一treatmenttemPerature;thecomPatibilities witheleetrolytes 产目录 摘要·····“·······”·“····”·”·”·······”······一·“·“·“·“·“·“·“·”·”·············“·“···一”·“二 A加位以··”··········“·“····