Electrochemical Tuning-Induced Magnetic Transitions in Geometrically Frustrated Spinel - Information et al. - Unknown - Unknown

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SupplementaryInformationElectrochemicalTuning-InducedMagneticTransitionsinGeometricallyFrustratedSpinelLixMn2O4(0.07≤x≤0.93)QiChen,1ZhongyueZhang,2*andKunioAwaga1,3*1.DepartmentofChemistry,NagoyaUniversity,Furo-cho,Chikusa-ku,Nagoya464-8602,Japan2.ResearchCenterforMaterialsScience,NagoyaUniversity,Furo-cho,Chikusa-ku,Nagoya464-8602,Japan3.IntegratedResearchConsortiumonChemicalSciences,Furo-cho,Chikusa-ku,Nagoya464-8602,JapanZZ:zhang.zhongyue@i.mbox.nagoya-u.ac.jpKA:awaga@mbox.chem.nagoya-u.ac.jpTableofcontentsS1.Magneticsusceptibilityforas-preparedLiMn2O4S2.ElectrochemicalperformanceforLi-LiMn2O4batteryS3.Rietveld'srefinementofXRDpatternsS4.InductivelycoupledplasmaopticalemissionspectroscopyforLixMn2O4S5.DCsusceptibilityforx=0.93and0.07S6.ACsusceptibilityforLixMn2O4(0.07≤x≤0.93)S7.Cole-ColeanalysisforLi0.50Mn2O4S8.DMinteractionsintheLixMn2O4systemS9.MagneticpropertiesforLi0.50Mn2O4S1

1S10.SpecificheatforLixMn2O4anditscalibrationS11.ReferenceS2

2S1.Magneticsusceptibilityforas-preparedLiMn2O4(a)(b)(c)(d)FigureS1.(a)Zero-field-cooled(ZFC)andfield-cooled(FC)magneticsusceptibilityand(b)inversesusceptibilityofas-preparedLiMn2O4.Theinsetin(b)isthederivativesofinversesusceptibility,andthearrowsin(b)pointouttheVerweyphasetransitiontemperatureof280K.(c)Realpartand(d)imaginarypartofACsusceptibilityofas-preparedLiMn2O4atfrequencyof2,19,199,997Hz.NotethattheDC/ACsusceptibilityofas-preparedLiMn2O4isverydifferentfromthatofelectrochemicalinducedLi0.93Mn2O4(x=1).Here,ACsusceptibilityonlyshowsweakfrequencydependencebelow10K.ThisisprobablyduetoadecreaseintheaveragegrainsizeS3

3aftertheelectrochemicalprocessinx=0.93,whichwouldgeneratemoresymmetry-brokenstructuraldefectsandresultaneffectiveferromagnetism1.S4

4S2.ElectrochemicalperformancesforLi-LiMn2O4battery(a)(b)(c)FigureS2.(a)Differentialchronopotentiometriccurve(dQ/dV),(b)cyclicvoltammetry(CV)curveand(c)cyclicperformanceforLi-LiMn2O4battery.TheCVanalysiswasperformedinthevoltagerangeof3.6-4.5V(vs.Li+/Li)atascanrateof0.5mV/sbyatwo-electrodesmode(BioLogicSP-150).S5

5S3.Rietveld'srefinementofXRDpatterns(a)(b)(c)(d)(e)S6

6(f)(g)(h)(i)(j)(k)S7

7(l)FigureS3.(a)ThecomparisonplotofpowderX-raydiffractionpatternsforLixMn2O4(0.07≤x≤0.93).(b-l)RietveldrefinementofpowderX-raydiffractiondataforLixMn2O4(0.07≤x≤0.93)byGSASsoftware2.Theexperimentaldataareshownasblackcross,andthecalculatedpatterns,backgrounds,differencesareplottedasred,greenandbluesolidlines.xvalueLatticeConstanta(Å)χ2RwpRp0.938.24503(11)1.42214.84%11.40%14/16(≈0.88)8.23969(10)0.927213.53%10.41%13/16(≈0.81)8.23142(11)0.928413.39%10.06%11/16(≈0.69)8.20810(10)0.862512.61%9.72%9/16(≈0.56)8.18276(13)1.30214.98%11.76%0.508.16069(11)1.06913.79%10.69%7/16(≈0.44)8.15577(10)1.19214.76%11.19%8.15465(11)8.04751(14)5/16(≈0.31)0.880612.62%9.66%57.14wt%42.86wt%8.15364(25)8.04622(9)3/16(≈0.19)0.716211.77%8.90%27.83wt%72.17wt%8.1498(5)8.04484(10)2/16(≈0.13)0.833912.33%9.50%18.55wt%81.45wt%0.078.04388(8)1.15013.45%10.08%TableS1.RefinedresultsfrompowderX-raydiffractiondataforLixMn2O4(0.07≤x≤0.93)S8

8S4.InductivelycoupledplasmaopticalemissionspectroscopyforLixMn2O4ThestoichiometryofLixMn2O4wereconfirmedusinganInductivelyCoupledPlasma-OpticalEmissionSpectrometer(ICP-OES)(VISTA-PROaxialCCDspectrometer,Agilent).Thelithiumstandard(1000mg/L),manganesestandard(1000mg/L)andnitricacid(60.0%~61.0%,forultratraceanalysis)werepurchasedfromFUJIFILMWakoPureChemicalCorporation(Osaka,Japan).Theas-preparedLiMnO4(around10mg)andthedischargedelectrodes(containsLixMn2O4,SuperPandPVDF)weredigestedwith120μlofHNO3(60%)and50μlofH2O2(35%).Forthedischargedelectrodes,theSuperPandPVDFremainedassolidresidue,whichwasfilteredofftogetaclearsolution.Theobtainedsolutionsweredilutedto200mLusinga1%nitricacid,withtheLiconcentrationaround0.2~3ppmandMnconcentrationaround30~50ppm.TheinstrumentparametersofICP-OESmeasurementsareshowninTableS2.RFpower1200WIntegrationtime15sPlasmagasflow(Ar)15L/minReaddelay20sNebulizergasflow(Ar)0.75L/minRinse20sAuxiliarygasflow(Ar)1.5L/minLiemissionline(nm)610.365,670.783Replicates5Mnemissionline(nm)257.610,259.372TableS2.ICP-OESoperatingconditions.TableS3showstheICP-OESresultsforas-preparedLiMn2O4andLixMn2O4(x=0.07,0.50,0.93),whicharegoodagreewiththeelectrochemistryobtainedstoichiometry.EmissionLineas-preparedLiMn2O4Li0.93Mn2O4Li0.50Mn2O4Li0.07Mn2O4(nm)ContentMoleContentMoleContentMoleContentMole(ppm)(mol)(ppm)(mol)(ppm)(mol)(ppm)(mol)Li(610.365)1.79980.25931.87620.27030.90770.13080.10560.0152Li(670.783)1.83260.26401.92130.27681.01150.14570.12680.0183S9

9Mn(257.610)29.0680.529132.1780.585728.8410.525020.4990.3731Mn(259.372)28.4830.518531.8090.579028.5650.520020.1930.3676Calculatedx0.99930.93950.55530.0904TableS3.ICP-OESresultsforas-preparedLiMn2O4andLixMn2O4(x=0.07,0.50,0.93).S10

10S5.DCsusceptibilityforx=0.93and0.07(a)(b)FigureS5.Temperature-dependentZFCandFCmagneticsusceptibilityχfor(a)Li0.93Mn2O4and(b)Li0.93Mn2O4.TSGisthestaticspinglasstransitiontemperature,whichisdeterminedbythelocalmaximumofZFCcurvesintheχ-Tplot.Tfisthefreezingtemperatureofspinglassstate,whichisdeterminedbyfrequencydependentpeakinACsusceptibility(Figure3).TNislongrangeantiferromagneticorderingtemperatureforLi0.07Mn2O4.S11

11S6.ACsusceptibilityforLixMn2O4(0.07≤x≤0.93)(a)(b)(c)(d)(e)(f)S12

12(g)(h)(i)(j)(k)FigureS6.ACsusceptibilityforelectrochemicalinducedspinelLixMn2O4(0.07≤x≤0.93)underanACfieldof2Oeat2HzwithoutDCbiasfield.Topcurves:realpartsofACsusceptibility.Bottomcurves:imaginarypartsofACsusceptibility.S13

13S7.Cole-ColeanalysisofLi0.50Mn2O4(a)(b)(c)FigureS7.(a)ArganddiagramforLi-230.50Mn2O4at40Kfrom10to10Hz.Thefrequencydependenceofthe(b)realpartand(c)imaginarypartACsusceptibilityforLi0.50Mn2O4Accordingtocole-coleequation,thecomplexsusceptibilitycanbewrittenas:?0−???(?)=??+1+(???)1−?S7.1?where?0and??aretheisothermal(ω→0)andadiabatic(ω→∞)susceptibilities,respectively,and??ismedianrelaxationtimeandαisaparameterwhichdeterminesthedistributionofrelaxationtime.3Whenα=1correspondstoaninfinitelywidedistribution,showingafrequencyindependentbehavior,whileα=0reducestotheDebyeequationofasinglerelaxationtime,showingasemicircleshouldbedetected.Theseparationofthecomplexsusceptibilityisshownasfollows,S14

14??′?0−??sinh(?)′′?0−??cos2?(?)=??+(1−??);?(?)=(??)2cosh(?)+sin2cosh(?)+sin22(S7.2),where?=(1−?)ln???.S15

15S8.DMinteractionsintheLixMn2O4system.FigureS8.DzyaloshinskiivectorsDij(i

16S9.MagneticpropertiesofLi0.50Mn2O4(a)(b)(c)(d)(e)(f)FigureS9.(a)DCsusceptibilityanditsnumericalderivativeofLi0.50Mn2O4underamagneticfieldof5kOe.(c)ThederivativeofisothermalsusceptibilitydM/dH.(d)ThefielddependenceS17

17oftherealpartofACsusceptibilityat16K,5Kand2KforLi0.50Mn2O4.(e)TheisothermalmagnetizationofLi20.50Mn2O4atvarioustemperature,and(f)itsArrottplot,H/MagainstM.TohighlightthenonlinearAFMphaseattheintermediatefieldsfrom0.5to20kOe,wemeasuredthemagneticsusceptibilityforx=0.50inZFCandFCmode(χZFCandχFC)underthemagneticfieldof5kOe,whichwas10timeslargerthanthefieldforFigure2(b).AsshownbytheresultsinFigureS9(a-b),thedivergencebetweenχZFCandχFCwasonlyobservedbelow16K.Thisbehaviorindicatesthattheshort-rangeAFMorderappearingat500OeinFigure2(b),andtheclusterspin-glassstateconcludedinFigure3(b),arequenchedunderthestrongmagneticfieldof5kOe,atwhichthecantedspinsarereorientedandthethermalirreversiblebehaviorofχZFCandχFCarevanished.Unlikeinthecaseofthisspin-glassstateandshort-rangeordering,thenoncollinearantiferromagneticphasecanpartiallysurviveevenunderthespinreorientationat5kOe.ThisindicatesthepresenceofastrongDMinteraction,whichpresumablyproducesalong-rangeamgenticordering.InFigureS9(c),thecuspsatthelowmagneticfieldarerelatedtothehysteresisloopsinFigure4(d),theconstantvaluesofdM/dHabove2kOeareexplainedbyagradualfield-inducedtransformationfromtheantiferromagneticstatetoaparamagneticstate.Owingtothecontributionofnoncollinearantiferromagneticorder,thetransitionregionscanbefoundbetweenlow-fieldcuspandhigh-fieldhorizontalline,especiallyattemperatureof5K.S18

18S10.SpecificheatforLixMn2O4anditscalibration(a)(b)(c)(d)FigureS10.Specificheatfor(a)Li0.93Mn2O4,(b)Li0.50Mn2O4,(c)Li0.07Mn2O4aftercalibration,plottedasCvs.T,and(d)theheatcapacityofthemixtureofcarbonblackandPVDFwithamassratioof1:1.Uptonow,wecannotobtaintheexactvalueofmagneticspecificheatCmbyremovingthelatticecontributionClattfromthetotalspecificheatCp,duetothelackofnon-magneticisostructuralanalogandshort-rangeantiferromagneticcorrelationpersistsevenataround200K.TheLixMn2O4areinsulatinginthewholetemperaturerange,whichhavealreadybeenwellinvestigated5,sotheelectronicspecificheatCecanbeneglected.S19

19AccordingtotheDebye’smodel,thelatticespecificheatatlowtemperature(T<<θD)canbeevaluatedby6:31/312?ℎ????3???=???4(),?=[()]??5???4??whereristhenumberofatomsperformulaunit,Nisthenumberofformulaunitperunitcell,Visthevolumeofunitcell,andceffistheeffectivesonicvelocitywhichisassumedtobethesameforLi4/3Ti5/3O4andLi0.07Mn2O4.ForthecubicspinelLi4/3Ti5/3O4,r=7,N=8,V=584.067Å3,andthecubicspinelforLi30.07Mn2O4,r=6,N=8,V=518.943Å.Therefore,theDebye’stemperatureofLi0.07Mn2O4canberoughlyestimatedbyscalingtheDebye’stemperatureofLi4/3Ti5/3O4(θD=610K)by0.889.ThelowtemperaturelimitoflatticespecificheatofLi0.07Mn2O4isshownas:3?J??=??≈6×1944()[∙K]=0.889??(Li4Ti5O4)0.988×?(Limole33?4Ti5O4)33Byapplyingthisapproximation,thecontributionoflatticespecificheatcouldbeseeninFig.6(c),whichisverysmallcomparedwithtotalspecificheat.Inotherwords,theentropylossbelow30Kforx=0.07mainlyoriginatesfromtheformationoflong-rangeorder.S20

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