Surface Modification and Performance Enhancement of Carbon Derived from Chromium Carbide for Supercapacitor Applications

Modified-chromium carbide-derived carbons have been successfully prepared by chemical extraction of chromium atom from chromium carbide via chlorination and subsequent treatment with 16 M HNO 3 . The pore structure and physicochemical properties of the as-prepared modified chromium carbide-derived carbons were characterized by nitrogen adsorption/desorption isotherm, X-ray photoelectron spectroscopy, X-ray diffraction, and contact angle measurements. The electrochemical performance was investigated by cyclic voltammetry, galvanostatic charge/discharge tests, electrochemical impedance spectroscopy, and cycle life measurements. The results show that the functionalities have been introduced to the surface of the chromium carbide-derived carbon after modification with nitric acid, and that the modified chromium carbide-derived carbon presents better electrochemical performance due to the improved wettability and pseudocapacitance. Particularly, the modified chromium carbide-derived carbon treated with HNO 3 in 100°C (C(Cr 3 C 2 )-M100) obtained a specific capacitance of 206.5 F g −1 at a current density of 1 A g −1 , whereas it was only 91 F g −1 for the pristine chromium carbide-derived carbon. In addition, the supercapacitor using C(Cr 3 C 2 )-M100 as electrode material had small resistance and excellent cyclic stability with high capacitance retention of 90%. The remarkable improvement of the electrochemical performance makes the modified chromium carbide-derived carbon a promising candidate for supercapacitors.