Design and exploring the synergistic potential of Ni-Co2-S4/rGO composite electrode for high performance flexible hybrid supercapacitors

Abstract

A one-step hydrothermal method is employed to synthesize a composite of nickel-cobalt sulfide (NiCo₂S₄) integrated with reduced graphene oxide (rGO) as an electrode for energy storage applications in the supercapcitor. The distribution of NiCo₂S₄ nanoparticles on the rGO surface is optimized to be enhance the supercapacitor performance. The resulting NiCo₂S₄/rGO composite showed impressive electrochemical characteristics such as capacitance (C) and specific capacitance (Cs) of 1950 F g⁻¹ at a current density of 1 Ag⁻¹. Furthermore, investigation of constructing a hybrid supercapacitor (HSC) using a NiCo₂S₄/rGO positive electrode and a graphene oxide (GO) as negative electrode, respectively. In the configuration achieved exceptional specific energy (Es) of 41.52 W h kg⁻¹ at a specific power (Ps) of 1067 W kg⁻¹, surpassing previous NiCo₂S₄ based supercapacitors. The HSC maintained an Es of 36.51 Wh kg⁻¹ at a Ps of 2065 W kg⁻¹ and exhibited an outstanding cycling stability also retaining 82% of its capacitance after 3000 charge-discharge cycles. Thus, the prepared materials are findings of the NiCo₂S₄/rGO composite one of suitability for advanced supercapacitors.