Synthesis, Fabrication, and Performance Evaluation of Nickel-Cobalt Sulfide Nanostructures for Enhancing Energy Density of Supercapacitors in Energy Storage Applications

Supercapacitors are useful for storing and delivering more energy in smaller footprints. Developing high-energy-density supercapacitors enables more efficient utilization of energy, improved performance, and a means for flexibly addressing diverse energy storage requirements. The electrode materials and the techniques used for their fabrication play a significant role in obtaining the desired operating performance of supercapacitors. The present study employs a novel, simple, scalable, and low-cost fabrication technique to synthesize nickel-cobalt sulfide (NiCo₂S₄) nanostructures on commercial nickel foam. Prominent morphological and electrochemical characterization techniques were used to assess the structural and operating performance of the synthesized nanostructure. The synergistic effects of nickel and cobalt transition metals resulted in enhanced performance of the nanostructure. The synthesized nanostructure was further employed in a symmetric supercapacitor device. Surface morphological and electrochemical experiments showed an energy density value of 62.8 Wh/kg and retention capacity of 94% even after 8000 cycles. The electrochemical characteristics were validated using electrical experiments as well. The high specific capacitance, faster electron and ion transfer, and improved structural integrity obtained for the supercapacitor indicate its suitability for enhanced energy storage applications.