Electrochemical supercapacitor performance of NiCo2O4 nanoballs structured electrodes prepared via hydrothermal route with varying reaction time

Nanostructured binary metal oxides have shown their potential for improved electrochemical performance due to their structural stability, electronic conductivity, and multiple oxidation states. Herein, uniform NiCo2O4 nanoballs were successfully prepared using the chemical hydrothermal process with various reaction times (5 h, 8 h, 14 h) followed by characterizations and investigation for supercapacitive properties. Nanoballs prepared at 14 h reaction time demonstrated the highest supercapacitor performance, owing to features microstructure and synergetic effect. Nanoballs have the highest electrochemical active surface area and transfer coefficient. The surface capacitive contribution of the NCO-SH-14h electrode is greater with a higher electrochemically active surface area. The contribution of surface capacitance is increased when the minimum relaxation period. The NiCo2O4 nanoballs have shown remarkable electrochemical performance with a specific capacitance of 1144 F/g and areal capacitance of 242 mF/cm2, and good stability of 5000 cycles. The NiCo2O4 nanoballs prepared at optimal hydrothermal reaction time (14 h) could be beneficial in energy storage applications with high energy and power density. Schematic representation for synthesis of NiCo2O4 nanoparticle via hydrothermal process. [Display omitted]