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

Partially reduced graphite oxide (GOpr) prepared from natural as well as synthetic graphite was used as electrode material for supercapacitors in 1 M Et4NBF4 in acetonitrile electrolyte. As a function of the degree of reduction of graphite oxide (GO) the graphite layer distance was varied between 0.46 and 0.33 nm. The initial specific capacitance of all samples was negligibly small around the open circuit potential, which was in agreement with the small BET surface area of the reduced GO powder of around 5 m(2)/g. During the first potential cycle, however, electrochemical activation resulted in a specific capacitance of up to 220 F/g for samples with a graphene layer distance of 0.44 nm. The potential for anodic and cathodic electrochemical activation was found to be a function of the GO layer distance. Dilatometrie investigations showed a significant swelling and shrinking of the samples. (C) 2010 Elsevier B.V. All rights reserved.