Electrochemical capacitor behavior of copper sulfide (CuS) nanoplatelets

Copper sulfide (CuS) nanoplatelets have been fabricated by simple low temperature chemical bath deposition technique for electrochemical supercapacitor electrodes. The morphology and structural properties of the electrodes were analyzed using scanning electron microscopy and X-ray diffraction. The effect of heat treatment on electrochemical properties of CuS electrodes were examined by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge tests. Results show that bare and heat treated CuS has pseudocapacitive characteristic within the potential range of −0.6 to 0.3 V (vs. Ag/AgCl) in aqueous 1 M LiClO4 solution. The pseudocapacitance is induced mainly by lithium ions insertion/extraction with the CuS electrodes. The specific capacitance of 72.85 F g−1 was delivered by heat treated CuS film at a scan rate of 5 mV s−1 with an energy and power density of 6.23 W h kg−1 and 1.75 kW kg−1 at 3 Ag−1 constant discharge current which is comparatively higher than that of as deposited CuS electrode.