Preparation of spherical activated carbon with high electric double-layer capacitance

The preparation of optically anisotropic spherical carbon from coal-based isotropic pitch was investigated. NaOH and KOH were used as activating agents. Spherical carbon with or without pre-calcination was mixed with four times the amount of NaOH and KOH by weight. Capacitance was measured at 25°C in a two electrode system using 1 M Et₄NBF₄ in propylene carbonate as an electrolyte. The result shows that the high density and moderate reactivity of anisotropy spherical carbon balanced by the pre-calcination and moderate activation with NaOH was indicated in the high capacitance per volume.