Polyaniline-intercalated layered vanadium oxide nanocomposites—One-pot hydrothermal synthesis and application in lithium battery

/nanoscale|Nanoscale

Polyaniline-intercalatedlayeredvanadiumoxidenanocomposites—One-pothydrothermalsynthesisandapplicationinlithiumbattery

YupingChen,aGangYang,bZihuiZhang,aXiaoyanYang,aWenhuaHou*aandJun-JieZhu*a

Received15thApril2010,Accepted30thJune2010DOI:10.1039/c0nr00246a

Polyaniline-intercalatedlayeredvanadiumoxidenanocompositesweresuccessfullysynthesizedbyanone-pothydrothermalmethodandcharacterizedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),highresolutiontransmissionelectronmicroscopy(HRTEM),selectedareaelectrondiffraction(SAED),Fouriertransforminfrared

spectroscopy(FT-IR),andRamanspectroscopy.Theeffectsofreactionconditions,suchaspHvalueoftheprecursorsolution,reactiontemperatureandtime,andtheamountofanilineonthestructureandmorphologyoftheobtainedsamples,weresystematicallyinvestigated.Basedontheexperimentalresults,aninsituintercalation-polymerization-exfoliationmechanismwasputforwardforthe

formationoflayerednanocomposites.Theapplicationoftheresultinglayerednanocompositeasthecathodematerialinlithiumbatterywastestedandtheresultsshowedthatthepolyaniline-intercalatedlayeredvanadiumoxidenanocompositepreparedat140 Chadagoodcyclingperformanceandmightactasapromisingcathodematerialforhigh-energy-densityrechargeablelithiumbatteries.

Downloaded on 02 December 2010Published on 08 September 2010 on | doi:10.1039/C0NR00246A

Introduction

Vanadiumoxidesandtheirrelatedcompoundshavebeeninvestigatedbothextensivelyandintensivelyduetotheirnovelphysicochemicalpropertiesandpotentialapplicationsinlithiumbatteries,1electric eld-effecttransistors2–4andchemicalsensors.5,6Thelayeredstructureandredoxabilityofvanadiumoxidesallowtheinsertionofvariousguestspeciessuchaspoly-mers,leadingtotheformationofhybridmaterialswithamixedvalenceofvanadium(V4+/V5+).7Organic–inorganichybridstructureshavebeendesignedtoachievenewmaterialswithimprovedpropertiesbecauseofthesynergiceffectsoftheirconstituentsatamolecularlevel.8,9Speci cally,theintercalationofconductingpolymersintolayeredinorganichostshasbeenatopicofresearchinterestoverthepasthalfcentury.10–13Amongthefamilyofconductingpolymers,polyanilineisofgreatinterestbecauseitselectricalandopticalpropertiescanbecontrolledbyasimpleandreversibleacid–basedoping–dedopingprocess.14Polyaniline–vanadiumoxidehybridmaterial,anewkindofconductingpolymer/oxidebronze,hasreceivedmuchattentionbecauseofthemixedelectroniccharge-transportproperties10,15,16andpotentialapplicationsinlithiumsecondarybatteries,17–19sensors20andelectrochromicdevices.21Considerableeffortshavebeenmadeonthesynthesisofconventionalpolyaniline–vana-diumoxidehybridmaterialsviainsituoxidativepolymerization/intercalationofanilineinV2O5xerogel15,16,22andthelayer-by-layermethod,23respectively.However,thesemethodsofteninvolvelengthyprocedureswithseveralstepsandneedmore

KeyLaboratoryofMesoscopicChemistryofMOEandKeyLaboratoryofAnalyticalChemistryforLifeScienceofMOE,SchoolofChemistryandChemicalEngineering,NanjingUniversity,Nanjing,210093,P.R.China.E-mail:whou@;jjzhu@b

SchoolofChemistryandMaterialsEngineering,ChangshuInstituteofTechnology,Changshu,215500,P.R.China

Electronicsupplementaryinformation(ESI)available:Experimentaldata.SeeDOI:10.1039/c0nr00246a

a

time.Thus,itisnecessarytodevelopmoreef cientsyntheticmethodstosimplifypreparationproceduresandshortentime.Recently,thehydrothermalandultrasoundroutestopreparepolyaniline–vanadiumoxidehybridnanomaterialshavedrawnmoreattentioninthisregard.Forexample,C.Zhangetal.havereportedaone-stephydrothermalreactionbetweenanilineandperoxovanadicacidtopreparepolyaniline–vanadiumoxidehybridhierarchicalarchitectures.24Maltaetal.havereportedanultrasoundroutetosynthesizehybridvanadium–polyanilinenanowiresstartingfromcrystallineV2O5andaniline.25Never-theless,thesereportsaremainlyfocusedonthespeci cprepa-rationmethods,andthereisstilllittlework,whichisnotsystemized,ontheone-potsynthesisofpolyaniline-intercalatedlayeredvanadiumoxidenanocompositesandtheirapplicationinlithiumbattery.

Herein,wereportanef cientmethodforthecontrolledfabricationofpolyaniline-intercalatedlayeredvanadiumoxidenanocompositesviaafacileone-pothydrothermalroute.TheeffectsofthepHvalueoftheprecursorsolution,reactiontemperatureandtime,andtheamountofanilineonthestructureandmorphologyoftheresultingproductwerediscussedindetailandaninsituintercalation-polymerization-exfoliationformationmechanismwasputforward.Moreover,thepotentialapplica-tionoftheresultinglayerednanocompositeinthelithiumbatterywasinvestigated.

Experimentalsection

Preparationofsamples

Allreagentswereofanalyticalgradeandusedasreceivedwithoutfurtherpuri cation.Distilledwaterwasusedthroughout.Inatypicalprocedure,0.18gofV2O5powderswereaddedinto30mLofdistilledwaterandstirredfor10min.Then,60mLofanilinewereaddedintotheslurrysolution.ThepHvalueoftheprecursorsolutionwasadjustedtoabout3through