Effect of Ni dopant on the capacitive behavior of CuS for supercapacitor application

Metal sulfide nanomaterials are addressed as electrode for supercapacitor applications, but their utilization is constrained due to less stability and poor capacity performance. The doping strategy is a successful method for enhancing the capacitance nature, cyclic stability, and conductivity property. In this investigation, nickel-doped copper sulfide (Ni–CuS) with different concentrations was synthesized by using the facile hydrothermal approach to resolve energy storage issues. A number of approaches are used to evaluate the structure, purity, phases, material composition, textural aspects, and morphology. In comparison to other electrode materials, the Ni_0.007CuS electrode contains a substantial specific capacitance (C_s) value of 1485.355 F g⁻¹ with an impressive energy density (E_d) of 94.27 Wh Kg⁻¹ as well as power density (P_d) of 338 W Kg⁻¹. The stability analysis of Ni_0.007CuS exhibited 92.96% capacitance retention after 5000th GCD cycles with only minor structural degradation, as investigated with X-ray diffraction (XRD). The achieved finding from the electrochemical impedance spectroscopy (EIS) suggested that the Ni_0.007CuS exhibits the 1.68 Ω charge transfer resistance (R_ct). The two-electrode results show that Ni_0.007CuS contains a C_s of 620 F g⁻¹ and an E_d of 128 Wh kg⁻¹. Our research demonstrates that including of nickel dopant in the form of Ni_0.007CuS nanoarray enhances the efficiency of charge migration by facilitating a convenient route for the transfer of electrolyte ions. As a result, we conclude that these cathode materials are suitable for use in supercapacitor applications.