Facile synthesis of graphene based mixed metal sulphide nanocomposite for energy storage applications

Supercapacitors, often referred to as electrochemical capacitors, are becoming more and more common because of their high-power density, long lifespan, and low maintenance requirements. The cobalt sulphide, nickel sulphide, and graphene oxide (CoS/NiS/GO) nanocomposites were developed because of their low cost and superior electrochemical characteristics for use in supercapacitors. Powder X-ray diffractometry and X-ray photoelectron spectroscopy analyses were used to assess the phase purity of each material. Scanner electron microscopy (SEM)/ energy dispersive X-ray analysis (EDX) and transmission electron microscope (TEM) images were used to visualize the nanoscale morphology of the synthesized nanocomposite. With a standard three-electrode setup, platinum sheet was used as the counter electrode and Ag/AgCl was used as the reference electrode for all electrochemical studies. The working electrode was a composite made of graphene oxide on CoS, NiS, and nickel foam. In a solution of 3 M KOH, all electrochemical measurements were conducted. In comparison to the corresponding Rct (41.35 l.cm2) and Rf (55.62 l.cm2) for the GO electrode, the Rct and Rf for the CoS/NiS/GO electrode were found to be 1.99 l.cm2 and 2.70 l.cm2, respectively. This suggests that the CoS/NiS/GO electrode has significantly lower overall impedance, which could be one of the major contributing factors to the enhanced electrochemical performance of the CoS/NiS. The electrode made of CoS/NiS/GO nanocomposite has a specific capacitance of 1114 mAh/g at current density of 5 A/g. After 8000 charge-discharge cycles, CoS/NiS/GO electrodes with a current density of 5 A/g still had 80% of their original specific capacitance. The CoS/NiS/GO samples have been shown to have energy densities and power densities of 674.12 Wh/kg and 8089.44 W/kg, respectively. Galvanostatic charge/discharge experiments reveal that the CoS/NiS/GO nanocomposite has a high specific capacitance and a long cycle life.