Effects of transition metal oxides on the formation of meso-porous structures in micro-spherical activated carbon for use in electric double layer capacitors

The effects of transition metallic oxide catalysts on the formation of meso-porous structures in micro-spherical activated carbon were investigated to improve the materialʹs performance as electrodes in EDLCs. Manganese, nickel and cobalt oxides were used as catalysts. Cobalt oxide strongly aided the formation of meso-porous structures. Despite having similar properties to cobalt, nickel and manganese were unable to achieve comparable meso-porous structures. Increased concentrations of cobalt oxide suppressed the formation of micro-pores and reduced the specific surface area. Pores of radii 25–60 Å were promoted and the volume of meso-pores increased. EDLCs employing activated carbon electrodes with meso-porous structures showed little reduction of electrostatic capacitance due to the meso-porous structures but exhibited improved charge transfer resistance and recharge capability.