Preparation of an electrochemically modified graphite electrode and its electrochemical performance for pseudo-capacitors in a sulfuric acid electrolyte

A graphite electrode was activated using recurrent electrochemical galvanic pulses. After activation, the original smooth surface was changed into an obviously porous, rough surface with microcrystalline flake structures with a larger number of O-containing functional groups. The material had a high capacitance and a satisfactory high-rate performance. The superior volumetric capacitance in active layer was ca. 428 F cm−3. Eighty-eight percentage of the capacitance remained after the discharge current increased from 2 mA (1.71 F cm−2) to 100 mA (1.50 F cm−2) in 2.3 M H2SO4.