High-Capacity Nickel-Doped ZnS Electrodes: A Cost-Effective Solution for Advanced Supercapacitors

This study employs a cost-effective chemical co-precipitation method to enhance zinc sulfide (ZnS) for supercapacitor applications through nickel (Ni) doping. ZnS samples with varying Ni concentrations (1%, 3%, and 5%) were synthesized and analyzed for electrochemical performance. Nickel doping significantly enhanced the specific capacitance of ZnS, with the Ni 3%-ZnS sample achieving 893.5 F/g at a scan rate of 10 mV/s, compared to 460.7 F/g for undoped ZnS. Structural and morphological studies confirmed uniform incorporation of Ni ions into the ZnS lattice, leading to reduced crystallite size and enhanced porosity. Electrochemical analyses in a three-electrode setup revealed that Ni doping improved ion transport, decreased charge-transfer resistance, and enhanced charge–discharge kinetics. The Ni 3%-ZnS electrode demonstrated excellent cyclic stability, retaining high capacitance after 1000 cycles. These improvements, attributed to an optimized pore structure and increased surface area, highlight the potential of Ni-doped ZnS as an efficient electrode material for supercapacitors.