Supercapacitors and energy conversion structures based on WS2 and MoS2 disulfides

Abstract

Abstract In this paper, disulfides WS2 and MoS2 were successfully prepared using thermal decomposition and utilised for fabrication of supercapacitor- and water splitting electrodes. Both, energy storage and conversion performances of these electrodes were compared with electrodes prepared with commercial MoS2, WS2, and activated carbon (AC). The electrochemical characterisation confirmed the pseudocapacitive character of disulfide-based supercapacitor electrodes. A strong influence of the scan rate on the specific capacitance was found, which is due to the diffusion of ions and the pseudocapacitive nature of charge storage. A specific capacitance of 405 mF/cm2 at 10 mV/s scan rate was achieved on MoS2 structures prepared by thermal decomposition. This value is 3.5-times greater than the capacitance achieved on commercial MoS2 and 6.8-times greater than capacitance achieved on structures with activated carbon. A specific capacitance of 396 mF/cm2 at 10 mV/s scan rate was achieved on WS2 structures prepared by thermal decomposition, which was 2.2 and 6.7-times greater than the capacitance achieved on commercial WS2 and AC based electrodes, respectively. Water-decomposition structures showed greater catalytic activity of thermally decomposed disulfides for HER compared to commercial materials and AC. The study showed a high perspective of MoS2 and WS2 prepared by thermal decomposition for energy storage applications by means of supercapacitors and energy conversion trough water electrolysis and hydrogen generation.