Fast response supercapacitor based on carbon-VS2 electrodes with a wide operating voltage range

Abstract

The presented work has undertaken a rational design of composite electrodes based on three-dimensional graphene-like (3DG) and transition metal-dichalcogenide (TMD), i.e., VS2. The aim was to expand the working voltage of TMD-based electrochemical capacitor (EC) in an aqueous medium above the thermodynamic limits. It has been found that designing the electrode material with a low proportion of edge to basal sites decreases the roughness of the electrode surface, and therefore, the possibility of water decomposition. The assembled cell based on the optimized composite electrode operating with lithium nitrate (1M) delivered a stable performance in a wide voltage range up to 1.8 V. Promising cyclic stability with capacitance retention of 80% after 7500 cycles at 1 A g−1 was recorded. The engineered structure of the electrode allowed the cell offering a superfast response with capacitive behavior even at a high scan rate of 3000 mV s−1. In addition, the cell delivered a high energy density of 18 Wh kg−1 at the power density of 430 W kg−1 at a current density of 1 A g−1. At high current density of 100 A g−1 the supercapacitor presented an energy density of 12 Wh kg−1 at the power density of 31000 W kg−1.