▎ 摘　　要

A simpleand efficient hydrothermal route was employed in thisstudy to synthesis nickel sulfide (NiS2) and its compositewith reduced graphene oxide (RGO). Spectroscopic and electrochemicalanalyses were carried out to confirm the formation of products. Itwas found that there were formations of unique hollow spheres, andthe surface of the sphere comprised NiS2 cubes and theRGO nickel sulfide (RGO/NiS2) composite evolved in theform of a cauliflower. The catalytic activity of the modified electrodedecorated with RGO nickel sulfide (RGO/NiS2) composite(1 mg cm(-2)) yields a CE of 77% and energy capacityof 850 mA h in the case of a vanadium redox flow battery having a132 cm(2) large electrode. It also served as a better electrodefor the super capacitor and was able to achieve a maximum specificcapacitance of 1136 F g(-1) at 2 mV/s. From the lifecycle study, it has been found to have a retention of Coulombic efficiencyof 74.3% up to 5000 cycles. Thus, the developed material can be employedas a superior electrode material for energy storage devices.