Fabricating controllable hierarchical pores on smooth carbon sheet for synthesis of supercapacitor materials

A smooth and defectless carbon sheet with thickness of 1-2 mu m was prepared by loose medium component from coal. Then, porous carbon sheet materials were prepared by activation of the carbon sheet using KCl and KOH under 750 degrees C and N-2 atmosphere. Such materials have lattice defect and porous structure which were verified by emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and N-2 adsorption-desorption. Their electrochemical performances were studied by cyclic voltammetry curves and constant current charge-discharge curves. The results showed that varing the content of KCl could control the distribution of the mesopore so as to change the specific capacitance. When carbon/KCl/KOH was at a mass ratio of 1:3:4, the specific capacitance reached up to 346 F g(-1) at the current density of 0.1 A g(-1) with high energy density and power density of 12 Wh kg(-1) and 25 W kg(-1), respectively. The high specific capacitance of this material was corresponded to its porous structure with high specific surface area of 3627 m(2) g(-1). Based on the above structure features and performance results, this paper supplies a brand new and promising way for synthesis of supercapacitor materials.