Self-promoted Nickel-chalcogenide Nanostructures: A Novel Electrochemical Supercapacitor Device-design Strategy

Abstract

Self-grown nickel-chalcogenides viz ., sulphide (NiS), selenide (NiSe), and sulfoselenide (NiSSe) nanostructures of the aligned nanorod, nanosheet, and nanobud-type morphologies are successfully synthesized through one-pot hydrothermal synthesis route on 3-D nickel-foam (NiF). The precursors of sulfur and selenium break down into S 2− and Se 2− ions, which then react with oxidized Ni 2+ ions on the surface of pure NiF to make NiS, NiSe, and NiSSe superstructures. The structural, morphological, and chemical states of as-grown Ni-based electrodes are monitored through various measurement tools. The as-obtained Ni-based NiS, NiSe and NiSSe electrode materials of various morphologies endow specific capacitances and specific capacities, at a current density of 3 A g −1 , of 1683.5 F g −1 , 1563.6 F g −1 , and 3314.9 Fg −1 and 187.05, 173.86, and 368.32 mAh g −1 respectively, in a three-electrode system containing 1.0 M KOH electrolyte solution. The NiSSe demonstrating the highest specific capacitance and outstanding chemical stability compared to other electrode materials might be due to the synergistic effect to improve overall electrochemical activity. In addition, the NiSSe electrode is chemically stable and mechanically robust as it doesn't detach from the conductive NiF substrate even at a high current density. Consequently, the as-designed NiSSe//NiSSe symmetric supercapacitor assembly divulges1658.6 Wkg −1 power density and 19.21 Whkg −1 energy density with the cycling stability of 93.48%. Connecting two cells in a series a panel “CNED” composed of nearly forty-two LEDs is ignited with high light intensity, adducing the practical importance of mixed metal chalcogenide electrode material in the energy storage sector.