Polystyrene-based carbon spheres as electrode for electrochemical capacitors

A series of carbon spheres with various porous texture parameters were prepared from polystyrene-based macroreticular resin spheres by carbonization and activation. The as-prepared carbon spheres had a maximum specific surface area of 996 m2 g−1, total pore volume of 1.34 cm3 g−1 and average pore size of 5.39 nm. Moreover, these carbon spheres showed a mesopore size distributed mainly in about 40 nm. A high specific capacitance of 153 F g−1 for carbon sphere by carbonization, 164 F g−1 for carbon sphere by activation for 1 h and 182 F g−1 for carbon sphere by activation for 2 h can be obtained. Moreover, a specific energy between 2.3 and 5.1 Wh kg−1 for these carbon spheres can be obtained in 6 mol L−1 KOH electrolyte.