Combined Effect of Nitrogen- and Oxygen-Containing Functiona

Combined Effect of Nitrogen- and Oxygen-Containing Functional Groups of Microporous Activated Carbon

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EffectofNitrogen-andOxygen-Containing

GroupsofMicroporousActivatedCarbononElectrochemicalPerformanceinSupercapacitors

DenisaHulicova-Jurcakova,MykolaSeredych,GaoQingLu,andTeresastandingwhethermicroporesonly,[1–5]acombinationofmicroporesandmeso-pores,[6–9]ormesoporesonly[10–13]areopti-malforthemosteffectiveutilizationofthesurfaceareainadouble-layerformation.Chmiolaandco-workers[14–16]presentedadifferentviewofporeaccessibilitytoions.

Theirresultsrevealedthattheporeswithawidthclosetothesizeofelectrosorbedions,i.e.,lessthan1nmfornon-aqueouselectro-lytes,arethemostactiveinadouble-layerformation.Thistheorywassupportedbyotherresearchgroups.[7,17]Inaddition,

Huangetal.recentlyrevealedauniversal

theoreticalmodeltoexplainthechargestoragemechanismapplicabletodifferent

porosity,carbonorigin,poresizedistribu-tionsandelectrolytes.[18,19]Thismodeltakestheporecurvatureintoaccount,incontra-dictionwiththetraditionalparallel-plate

capacitor,anditappearsthatinthemicroporeregimesolvated/desolvatedionslineupalongtheporeaxistoformanelectricwire-in-cylindercapacitor,whileinthemesoporeregimetheyapproachtheporewalltoformanelectricdouble-cylindercapacitor.Theelec-tricdouble-layercapacitormodelbecomesapplicableinthemacroporeregionwherethe

porecurvatureisnolongersigni cant.Itshouldbenotedthatthismodelwassuccessfullyappliedtocarbonswithunimodalpores

1.Introduction

anddominantelectrosorptionofionsanditmaynotbeapplicableincarbonswithpseudocapacitiveenergystoragemechanism.

Carbonelectrodematerialsforelectricdouble-layercapacitorsor

Theseincludecarbonswithnitrogen-andoxygen-containing

so-calledsupercapacitorshavebeenstudiedextensivelyinrecent

surfacegroups,whichhavebeeninvestigatedextensivelyinthelast

years.Oneofthemaininterestshasbeenfocusedonunder-decade.[20–26]Surfacegroupsintroducetheacid-basepropertiestocarbon[27–29]andgiverisetoFaradaicpseudocapacitivereac-[*]Prof.T.J.Bandosz,Dr.M.Seredychtions.[30]Pseudocapacitanceinnitrogen-enrichedcarbonshasTheCityCollegeofNewYork,DepartmentofChemistrybeenproposed,butnotcon rmed,astheoxidation/reductionof160ConventAve,NewYork,NY10031(USA)

negativelychargednitrogengroupslocatedattheperipheryofE-mail:tbandosz@ccny.cuny.edu

graphene-likelayers.[22]Inthecaseofoxygenfunctionalities,theDr.D.Hulicova-Jurcakova,Prof.G.Q.Lu

mostdocumentedcaseisthereversibleoxidation/reductionofTheUniversityofQueensland

ARCCentreofExcellenceforFunctionalNanomaterialshydroquinone/quinonegroups.[21,28,31]AustralianInstituteforBioengineeringandNanotechnologySinceoxygenfunctionalitiesarealwayspresentonthecarbonandSchoolofEngineering

surfaceasaresultofactivationprocessesorasaresiduefromtheCornerCollegeandCooperRoads,StLucia,4072QLD(Australia)

carbonsource,[32]thepseudocapacitivecontributiontothetotalcapacitanceofcarbonshouldbetakenintoaccount.Therefore,inDOI:10.1002/adfm.200801236438

ß2009WILEY-VCHVerlagGmbH&Co.KGaA,WeinheimAdv.Funct.Mater.2009,19,438–447