Investigation of graphene based NiS nanocomposite by solvothermal method for energy storage application

Fabrication of electrode with graphene-based material has received widespread interest in the specialization of energy-related devices. Especially in supercapacitors, engineering electrode material with graphene shows promising performance with enhanced energy and power density. In this work, graphene-nickel sulphide (G-NiS) hybrid nanocomposite was synthesized successfully by solvothermal method. The phase purity of the materials were determined from XRD studies. SEM image reveals deposition of NiS nanoparticles over the surface of graphene oxide layer forming a flower-like structure. The G-NiS nanocomposite electrode shows an excellent specific capacitance of 409.2F/g at low current density of 5 A/g in the three electrode cell. A symmetric supercapacitor based on G-NiS nanocomposite exhibited a high specific capacitance of 136.2F/g at 5 A/g and excellent cycling stability with coulombic efficiency of 98.1% after 1000 cycles. The high performance of the nanocomposite is mainly attributed to the presence of the NiS nanoparticles deposited on the graphene surface which readily produce more active sites for electron transport. Thus, the as prepared G-NiS nanocomposite could be an advanced supercapacitor electrode material.