A Synergistic effect of binary metal oxides NiMn₂O₄ nanocomposite decorated on rGO for energy storage supercapacitor application

In recent days, supercapacitors are emerging as an energy storage device. On account of it, this research work is based on NiMn₂O₄ incorporated on reduced graphene oxide (rGO) acts as an electrode for material for advanced supercapacitor application. One-pot hydrothermal technique was adopted to synthesise rNiMn₂O₄ nanocomposite with different ratios such as rNiMn₂O₄-10 and rNiMn₂O₄-20. The crystalline structure and morphology of the nanocomposites have been demonstrated by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis. From Brunauer–Emmett–Teller (BET) investigation, it is more precise that rNiMn₂O₄-20 possesses a large surface area of 328.9 m²g⁻¹ with mesoporous structure among all other nanocomposites. Further, the electrochemical measurements were probed in three electrode system such as Cyclic Voltammetry (CV), Galvanometric Charge–Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS). The synergistic effect from the as-synthesized nanocomposites withholds an outstanding electrochemical performance ascribing the impact of rGO present in it. Considering from GCD profile, rNiMn₂O₄-20 achieves a remarkable specific capacitance of 1284.8 Fg⁻¹ at a current density of 1 Ag⁻¹ in 1 M Na₂SO₄ electrolyte solution with a long term stability of 91.6% even after 5000 cycles at 3 Ag⁻¹. In consideration of all the above results, the as-synthesized nanocomposites has an outstanding electrochemical performance which leads to a new generation energy storage device in supercapacitor application.