Enhanced electrochemical performance of nanoplate nickel cobaltite (NiCo₂O₄) supercapacitor applications

Well-ordered, unique interconnected nanostructured binary metal oxides with lightweight, free-standing, and highly flexible nickel foam substrate electrodes have attracted tremendous research attention for high performance supercapacitor applications owing to the combination of the improved electrical conductivity and highly efficient electron and ion transport channels. In this study, a unique interconnected nanoplate-like nickel cobaltite (NiCo₂O₄) nanostructure was synthesized on highly conductive nickel foam and its use as a binder-free material in energy storage applications was assessed. The nanoplate-like NiCo₂O₄ nanostructure electrode was prepared by a simple chemical bath deposition method under optimized conditions. The NiCo₂O₄ electrode delivered an outstanding specific capacitance of 2791 F g^-1 at a current density of 5 A g^-1 in a KOH electrolyte in a three-electrode system as well as outstanding cycling stability with 99.1% retention after 3000 cycles at a current density of 7 A g^-1. The as-synthesized NiCo₂O₄ electrode had a maximum energy density of 63.8 W h kg^-1 and exhibited an outstanding high power density of approximately 654 W h kg^-1. This paper reports a simple and cost-effective process for the synthesis of flexible high performance devices that may inspire new ideas for energy storage applications.