Nickel sulfide and potato-peel-derived carbon spheres composite for high-performance asymmetric supercapacitor electrodes

In the present work, a novel composite of nickel sulfide (NiS) and potato peel-derived carbon spheres (NiS/PPCS) with higher specific capacitance and cyclic performance was synthesized as electrode material for supercapacitor applications. The composite was deposited on a graphite rod to be use as an electrode. The electrochemical performance studies using CV, GCD, and EIS revealed that the prepared electrode showed an improved current response and higher specific capacitance than the pristine NiS electrode. The maximum specific capacitance for the NiS/PPCS electrode was found to be 2185 F/g at 0.2 A/g current density. More precisely, it was observed that the NiS/PPCS composite exhibited an excellent retention capacity of 95.04% after 20 000 continuous charge-discharge cycles, showing its exceptional cyclic performance. The impedance studies revealed that the reaction between the NiS/PPCS electrode and electrolyte was rapid and highly reversible. Based on the findings of the electrochemical performances, NiS/PPCS electrode appears to be a potential candidate for highly efficient and economical asymmetric supercapacitors.