Structural characterization and electric double layer capacitance of template carbons

Novel carbon structure has been prepared from heterocyclic hydrocarbons, which contain a nitrogen atom, using a fluorine expandable mica as a template. The obtained carbon particles as a residue after acid washing of carbon/mica nanocomposite comprised two structural parts: very thin film and surrounding rim part. The latter rim part has constant width of about 20 nm. In addition, on account of the nitrogen atoms in the starting hydrocarbons, a certain amount (10–18 wt.%) of nitrogen remained in the resulting template carbon. These template carbons indicated a high electric double layer capacitance amounting to more than 100–180 F/g in H2SO4 electrolyte. Because of low surface area of the samples, specific capacitance per unit surface area could reach 1.2–2.2 F/m2, which is over 10 times as high as the capacitance of ordinary activated carbons. The capacitance decreased markedly with heat treatment temperature (>1000 °C) of the template carbon. Since the heat treatment accompanied the elimination of nitrogen from the sample, the presence of residual nitrogen may account for such a high capacitance.