Electrochemical behavior of exfoliated carbon fiber andgraphite in sulfuric acid electrolyte

摘要

The specific capacitance of exfoliated carbon fiber (ExCF) which was synthesized from pitch-based carbon fiber showedstrong dependence with the concentration of sulfuric acid electrolyte and reached 1.4 F/m2 in 18M H2SO4 solution. Sincethe capacitance value is quite large compared with the case of conventional activated carbons, the Faradic reaction (chargetransfer reaction) have to occur as a pseudo-capacitance. ExCF, however, gave a featureless cyclic voltammogram in 18MH2SO4 solution. In the case of exfoliated natural graphite, the intercalation of H2SO4 molecules is evidenced by the redoxpeak observed on the voltammograms at the same conditions. Therefore, the strong interaction between H2SO4 moleculesand ExCF surface might be a reason for the evolution of pseudo-capacitance on ExCF in H2SO4 electrolyte.