Novel Surface-Enriched Spiky Ball With Spines NiCo2S4@GO/CNT Electrode Material for a High-Performance Flexible Asymmetric Supercapacitor

Abstract

Nickel cobalt sulfide (NiCo2S4) nanoparticles on graphene oxide GO sheets and carbon nanotube (CNT) were fabricated successfully via a simple solvothermal route. Most NiCo2S4 nanoparticles cover both sides of the GO sheets, and the carbon nanotubes are arranged at the edge of the composite, creating a Spiky ball structure that effectively prevents the accumulation of GO. Synthesized hybrid nanocomposite (NiCo2S4/GO/CNT) has an optimum specific surface area and pore nature, and the coupling between CNT and GO enhances the electrochemical properties of NiCo2S4. The structural, morphological, and spectral characteristics were analysed using diffraction, microscopy, and spectroscopy techniques. To determine the electrochemical activity, cyclic voltammetry (CV), galvanostatic charge-discharge spectroscopy, and electrochemical impedance spectroscopy (EIS) were performed in a 3 M KOH electrolyte solution, the prepared sample was evaluated as an active electrode material for the supercapacitor. It delivers a very high specific capacitance of 845 Fg−1 at a current density of 2 Ag −1 as compared with NiCo2S4 (423 Fg−1). Coin cell was fabricated and tested using NiCo2S4/GO/CNT as cathode and graphite as an anode. The device exhibited an excellent energy density of 30.8 Wh kg−1, a power density of 3691 Wkg−1, and good cyclic stability with 82% retention after 1000 cycles.