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 m(2) g(-1), total pore volume of 1.34 cm(3) 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. (C) 2011 Elsevier Ltd. All rights reserved.