Synthesis of Nitrogen and Sulfur Co-Doped Carbon Derived from Chromium Carbide for the High Performance Supercapacitor

Nitrogen and sulfur co-doped carbons derived from chromium carbide (NSCDC) are successfully synthesized by chemical extraction of chromium atom from chromium carbide and followed by a facile hydrothermal treatment using thiourea as nitrogen and sulfur sources. The physicochemical and electrochemical properties of the as-prepared materials are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherm, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier infrared spectroscopy (FTIR), cyclic voltammetry (CV), galvanostatic charge/discharge tests (GCD), electrochemical impedance spectroscopy (EIS) and cycle life measurements. The results demonstrate that nitrogen and sulfur species are successfully incorporated into carbon derived from chromium carbide (CDC), and the obtained NSCDC can still maintain interconnected mesoporous carbon network which is favorable for rapid transport of electrolyte ions. Besides, NSCDC exhibits the enhanced wettability, improved conductivity and excellent supercapacitive performance generated from the incorporation of nitrogen and sulfur. The maximum specific capacitance of 281.2 F g−1 at 1 mV s−1 can be achieved for the NSCDC-4. Moreover, the NSCDC-4 supercapacitor possesses excellent cyclic stability with high capacitance retention of 95% after 6000 consecutive cycles. These exciting results reveal that NSCDC is a kind of promising electrode material for the high performance supercapacitors.