The effect of activation technology on the electrochemical performance of calcium carbide skeleton carbon

Porous CaC2-derived carbon (CCDC) was synthesized by one-step route from CaC2 in a freshly prepared chlorine environment at lower temperature. As-prepared CCDC was activated by H3PO4, ZnCl2, and KOH, respectively. The effects of the activation technology on the structure and morphology of CCDC were studied by X-ray diffraction, physical N-2 adsorption/desorption, and transmission electron microscopy. It has been found that the pore structure and specific surface area of CCDC are apparently improved after activation; the CCDC activated by KOH especially showed an excellent specific surface area of 1,100 m(2) g(-1). The electrochemical performance of supercapacitors using activated CCDC as electrode active material was studied by cyclic voltammery, galvanostatic charge/discharge, and cycle life measurements. The results indicated that the CCDCs activated by H3PO4, ZnCl2, and KOH revealed enhanced capacitances of 172.6, 198.1, and 250.1 F g(-1) in 6 M KOH electrolyte, which were increased by 11.4, 27.8, and 61.2 % compared with the pristine CCDC (155 F g(-1)), respectively. Furthermore, the supercapacitors using all activated CCDCs as electrode active material exhibited excellent cycle stability, and the specific capacitance for all activated CCDC samples had nearly no change after 5,000 cycles.