Eco-friendly preparation of nickel cobaltite as an electrode material in sustainable energy storage devices

In this study, urchin and tremella-like NiCo₂O₄ was synthesised by adopting a facile hydrothermal method using green solvents (water and ethanol). Using different ratios and pure forms of green solvents has a direct impact on materials synthesised. Ethanol based NiCo₂O₄ (NCO-E) illustrated tremella like microspheres with a specific surface area of 260.8 m² g⁻¹. The electrochemical performance confirmed that the NCO-E has a maximum specific capacitance of 2271 F g⁻¹ at a current density of 1 A g⁻¹. Further, as-fabricated NCO-E//AC-ASC device delivers a C_s value of 96.6 F g⁻¹ at 1 A g⁻¹ and a cyclic stability of 99.68 % over 5000 cycles. The device exhibited a high energy density of 30.19 Wh kg⁻¹ at a power density of 749.48 W kg⁻¹ and a high power density of 7542.61 W kg⁻¹ at energy density 18.43 Wh kg⁻¹ owing to the working electrode's effective electrochemical usage and excellent ion transfer mechanism.