Partially reduced graphite oxide for supercapacitor electrodes: Effect of graphene layer spacing and huge specific capacitance

abstract Article history:Received 25 October 2010Received in revised form 12 November 2010Accepted 15 November 2010Available online 24 November 2010Keywords:Electrochemical capacitorGraphite oxideGrapheneAprotic electrolyteDouble layer Partially reduced graphite oxide (GOpr) prepared from natural as well as synthetic graphite was used aselectrode material for supercapacitors in 1 M Et 4 NBF 4 in acetonitrile electrolyte. As a function of the degree ofreduction of graphite oxide(GO) thegraphitelayer distance wasvaried between 0.46and 0.33 nm. Theinitialspecific capacitance of all samples was negligibly small around the open circuit potential, which was inagreement with the small BET surface area of the reduced GO powder of around 5 m 2 /g. During the firstpotential cycle, however, electrochemical activation resulted in a specific capacitance of up to 220 F/g forsamples with a graphene layer distance of 0.44 nm. The potential for anodic and cathodic electrochemicalactivation was found to be a function of the GO layer distance. Dilatometrie investigations showed asignificant swelling and shrinking of the samples.© 2010 Elsevier B.V. All rights reserved.