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

Self-grown nickel-chalcogenides viz., sulphide (NiS), selenide (NiSe), and sulfoselenide (NiSSe) nanostructures of aligned nanorod, nanosheet, and nanobud-type morphologies have successfully been synthesized through one -pot hydrothermal synthesis chemical method on 3-D nickel-foam (NiF). The precursors of sulfur and selenium break down into S-2-and Se-2-ions, which on reacting with oxidized Ni2+ ions on the surface of phase-pure NiF produce NiS, NiSe, and NiSSe superstructures. The structural, morphological, and chemical states of the 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 3 A g(-1) current density, 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 electrode dem-onstrates the highest specific capacitance and outstanding chemical stability compared to other electrode ma-terials which is attributed to the synergistic effect of two separate metal chalcogenides. 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 divulges 1658.6 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 has been ignited with high light intensity, adducing the practical importance of mixed metal chalcogenide electrode material in the energy storage sector.

Automated summary

Self-grown nickel-chalcogenides nanostructures of various morphologies have been synthesized through one-pot hydrothermal synthesis. These structures demonstrate high specific capacitance and outstanding chemical stability, making them important in the energy storage sector.