Activation of Carbon Nanofibers and Their Application as Electrode Materials for Supercapacitors

Abstract

Surface activation of carbon materials produced by chemical vapor deposition onto a nickel plate is described. The products of pyrolysis of a gas mixture composed of propane, butane, and isobutane were for the most part nanofibers. This material was used as the active mass for electrodes of supercapacitors. The elec¬trodes were activated with a potassium hydroxide (KOH) at temperatures of 700 and 800°C in the atmosphere of argon. The activation efficiency was evaluated by the capacitance of supercapacitor cells by measurement of the electrochemical properties based on activated and unactivated materials. The salt 1.1-dimethylpyrrolidinium tetrafluoroborate (DMP) in acetonitrile (AN) was used as an electrolyte. The specific surface area of the electrodes was determined from adsorption data. It was shown that the specific surface areas of non-activated samples and samples activated at 700 and 800°C were 190, 338, and 586 m² g^-1, respectively. The specific capacitance of the samples also became higher with increasing specific surface area.