Synthesis of Cauliflower-like Reduced Graphene Oxide Nickel Sulfide Nanocomposites for the Vanadium Redox Battery and Supercapacitor Application
Sharath Kumar Basavaraju, Gireeshkumar Basavaraj Chavati, Arthoba Nayaka Yanjerappa, Krishna Venkatesh, Venkateswarlu Manne, H. B. Muralidhara
Abstract
A simple and efficient hydrothermal route was employed in this study to synthesis nickel sulfide (NiS 2 ) and its composite with reduced graphene oxide (RGO). Spectroscopic and electrochemical analyses were carried out to confirm the formation of products. It was found that there were formations of unique hollow spheres, and the surface of the sphere comprised NiS 2 cubes and the RGO nickel sulfide (RGO/NiS 2 ) composite evolved in the form of a cauliflower. The catalytic activity of the modified electrode decorated with RGO nickel sulfide (RGO/NiS 2 ) composite (1 mg cm –2 ) yields a CE of 77% and energy capacity of 850 mA h in the case of a vanadium redox flow battery having a 132 cm 2 large electrode. It also served as a better electrode for the super capacitor and was able to achieve a maximum specific capacitance of 1136 F g –1 at 2 mV/s. From the life cycle study, it has been found to have a retention of Coulombic efficiency of 74.3% up to 5000 cycles. Thus, the developed material can be employed as a superior electrode material for energy storage devices.