电极-离子液体界面电容

/111,*11,2,*(1,430072;2DepartmentofChemicalandEnvironmentalEngineering,FacultyofEngineering,TheUniversityofNottingham,NottinghamNG72RD,UK)BMIMPF6,BMIMBF4,BMIMClO4,BMIMTf2N,BMIMCl,BMIMBr,C3OHMIMBF4,C3OHMIMClO4BMMIMPF6(BMIM:1-butyl-3-methylimidazolium;C3OHMIM:1-(3-hydroxypropyl)-3-methylimidazolium;BMMIM:1-butyl-2-methyl-3-methylimidazolium;Tf2N:bis(trifluoromethylsulfonyl)amide).:、,,/-..,/,.,,.Li+/.BMIMTf2NLiTf2N,Li+/,,.,,/.;;/;;O646CapacitanceattheElectrode/IonicLiquidInterfaceZHAODi1HUANGQing1JINXian-Bo1,*WEIXian-Jun1CHENGeorgeZ.1,2,*(1CollegeofChemistryandMolecularScience,WuhanUniversity,Wuhan430072,P.R.China;2DepartmentofChemicalandEnvironmentalEngineering,FacultyofEngineering,TheUniversityofNottingham,NottinghamNG72RD,UK)AbstractTheinterfacialstructureandcapacitanceofaPtfoilelectrodewereinvestigatedbyelectrochemicalimpedancespectroscopyinvariousionicliquidsincludingBMIMPF6,BMIMBF4,BMIMClO4,BMIMTf2N,BMIMCl,BMIMBr,C3OHMIMBF4,C3OHMIMClO4andBMMIMPF6(BMIM:1-butyl-3-methylimidazolium,C3OHMIM:1-(3-hydroxypropyl)-3-methylimidazolium,BMMIM:1-butyl-2-methyl-3-methylimidazolium,Tf2N:bis(trifluoromethylsu-lfonyl)amide).Theresultsindicatethatwhentheanionandcationoftheionicliquidareofcomparablesizeanddonotadsorbspecificallyontheelectrode,the“capacitance-potential”curvenearthepotentialofzerochargeexhibitseitheronepeakortwopeaks.Thepotentialofzerochargecorrespondstoeitherthepeakpotentialorthevalleypotentialonthecapacitance-potentialcurvewithonepeakortwopeaks,respectively.Whenthepotentialispositiveornegativetothepotentialofzerocharge,thestructureofthe“electrode/ionicliquid”interfacecouldbeexplainedbythecompactlayertheories.Inthepresenceofspecificionadsorption,thecapacitancepeakdisappearsandwhiletheelectrodepotentialshiftsagainstthepotentialofzerocharge,theinterfacialcapacitancerapidlyincreases.TheeffectsofsmallLi+ionsontheelectrode/ionicliquidinterfacialstructureandcapacitancewerealsostudied.WhenLiTf2NwasaddedtoBMIMTf2N,thesmallLi+ionchangedtheioniccompositionandhencethestructureoftheelectrode/ionicliquidinterface,andalsodecreasedtheinterfacialcapacitance.Basedonthesefindings,thearrangementandconformationof[Article](WuliHuaxueXuebao)ActaPhys.-Chim.Sin.,2010,26(5)1239-1248MayReceived:November27,2009;Revised:January24,2010;PublishedonWeb:March22,2010.*Correspondingauthors.Email:[e-mail],[e-mail];Tel:[phone].TheprojectwassupportedbytheNationalNaturalScienceFoundationofChina(20773094,20973130),NationalKeyBasicResearchProgramofChina(973)(2007CB613801)andE.OnAG(InternationalResearchInitiative2007-EnergyStorage).(20773094,20973130),(973)(2007CB613801)E.OnAG(2007)鬁EditorialofficeofActaPhysico-ChimicaSinica1239ActaPhys.-Chim.Sin.,2010Vol.26、,(,ionicliquids,ILs),、、,.“/”,./,./,.,/,/.,.,,,,[1-5].,//.,,,(),/[6-7].,/.、/,/.1997,Koch[8],Hg.2004,Baldelli[9-13](SFG)BMIM+,/、./Helmholtz:BMIM+,,;,.FT-IR,,[14].,Alam[15-16]EMIMBF4、BMIMBF4、HMIMBF4N,N-DEMMEABF4(EMIM:1-ethyl-3-methylimidazolium;HMIM:1-hexyl-3-methylimidazolium;N,N-DEMMEA:N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium)Hg、,－(C-E)./.EMIMBF4OMIMBF4(OMIM:1-octyl-3-methylimidazolium),,C-E[17].Su[18]STM(scanningtunnelingmicroscopy)BMIMBF4Au(100),/、.,Gouy-Chapman-Stern.Kornyshev[19],,/(Kornyshev).、,,γ1/3,γ=(c++c-)/cmax,c+c-,cmax、),-(C-E),.,γ1/3,-(C-E)theanionsandcationsoftheionicliquidattheelectrode/ionicliquidinterfaceareelaboratedunderdifferentconditionswithparticularattentiontothespecificadsorptionofboththecationandtheanion.KeyWordsElectrochemicalcapacitance;Ionicliquid;Electrode/electrolyteinterface;Interfacialioncollocation;Electrochemicalimpedancespectroscopy1240No.5/,,.KornyshevGouy-Chapman.,-,.Oldham[20]Gouy-ChapmanStern/,γ=1/Kornyshev.Islam[21]DMOATf2N,TMPATf2N,DiAlIMTf2NBMPyrTf2N(DMOA:N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium;TMPA:N,N,N-trimethyl-N-propyl-ammonium;DiAlIM:1,3-diallylimidazolium;BMPyr:N-n-butyl-N-methylp-yrrolidinium)Pt、Au,PtAu/,C-EKornyshev;/,C-EKornyshev.[22-24]/,.,/,/.9C-E,.、/,(Li+)/.,、/.11.1CHI440();PARBESPowersuite();SZ-93();SY200();SC-15B().,BMIMPF6,BMIMBF4,BMIMClO4,BMIMTf2N,BMIMCl,BMIMBr,BMMIMPF6,C3OHMIMBF4C3OHMIMClO4[25-28].70℃12h..1.2,0.68cm×0.38cm..5min,,4,.1.3:(0.68cm×0.38cm)、(D=0.6cm),Ag/Ag+(0.01mol·L-1AgNO3,CH3CN).0.0713mol·kg-1LiTf2NBMIMTf2N.1.4CHI440,(CV);PARBESPowersuite,.Ar,1h,Ar,Ar.T=70℃.22.1-,.4V,4V,,[18],.,1-(C-E).1,.1(a)BMIM+C3OHMIM+,,.,,,0V.BMIMTf2NLiTf2N,(1(b)),LiTf2N,..(50kHz-1Hz,10mV)2(a),90°.,1241ActaPhys.-Chim.Sin.,2010Vol.26Zim=(2πfC)-1,Zim(2πf)-1(2(b))Pt/.,,-(C-E),34.3(BMIM+)C-E,,.,BMIMClO4,BMIMTf2N,BMIMBF4(3(a-c))C-E.BMIMPF6(3(d)),0V,,C-E.3(a-c)Kornyshev[19],BMIMClO4,BMIMTf2N,BMIMBF4,0.5.0.3-0.7[29].BMIMPF6C-E,.,,BF-4PF-6[10].3(e)3(f)BMIMBrBMIMClC-E,.Kornyshev,/BMIMCl[30],[21].,,.,,3(b-d),.Cl-、Br-,1242No.5/.,Cl-、Br-,.BMIMClO4C-E,,ClO-4,,ClO-4[31].4C-E.4(a,b)C3OHMIM+.BMIM+,C3OHMIM+C,,C-E.,.4(c)BMMIMPF6C-E,BMIMPF6,.Kornyshev,BMMIMPF6,BMIM+,BMMIMPF6BMMIM+2H,,PF-6.4(d)0.0713mol·kg-1LiTf2NBMIMTf2NC-E.BMIMTf2NLiTf2NLi＋,,/.CV(1(b)),4(d)C-E,.,LiTf2N,BMIMTf2NC-E(3(b))(4(d)).Korn