Surface N, O Functionalization of Calcium Carbide-derived Carbon and Its Electrochemical Performance

Porous CaC2-derived carbon (CCDC) was synthesized by one-step route from CaC2 in a freshly prepared chlorine environment at low temperature. CCDC was oxidized by HNO3 and treated with urea or melamine by carbonization at 950 degrees C in an inert atmosphere, then nitrogen-enriched CCDC was obtained. The samples were characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and elemental analysis. It found that the surface texture and chemistry activation of CCDC are improved by the containing nitrogen or oxygen functional groups preexisting on the surface. Electrochemical performances of supercapacitors using modified CCDC as electrodes were studied by cyclic voltammery, galvanostatic charge/discharge and cycle life measurements. The results showed that the HNO3, urea and melamine modified CCDC revealed enhanced capacitances of 181.5, 210.8 and 225.4 F.g(-1) in 1 mol/L H2SO4, which increase by 17.3%, 36.3% and 45.7% compared with the initial carbon, respectively. Furthermore, the capacitance of supercapacitors are nearly no change after 5000 cycles.