Bimetallic NiO/Mn2O3 nano-pyramids as battery-type electrode material for high-performance supercapacitor application

Abstract

Herein, we report the synthesis of bimetallic oxide (NiO/Mn2O3) as an efficient positive electrode for supercapacitor application prepared by a facile one-step composite hydroxide-mediated approach. Exceptional electrochemical performance has been achieved by optimizing the composition, structure, and morphology. Simple cubic crystal structure with bipyramid surface morphology provided a large specific surface area and more active sites for rapid transfer of ions between electrolyte and electrode. The electrochemical performance of prepared electrodes was examined in a three-electrode system, where nickel foam was used as a conductive support. From the electrochemical measurements, the NiO-50 % Mn2O3 exhibited the highest specific capacitance of 1730.5 F g−1 at a current density of 1.5 A g−1 in a 3 M aqueous KOH electrolyte. The optimized electrode showed long-term cycling stability of 4000 charge-discharge cycles at a high retention rate of 97.5 % at 10 A g−1, which supports the excellent performance of the electrode and robust stability. Hence, owing to its unique bipyramid-like morphology, outstanding performance, and easy one-step synthesis process, NiO/Mn2O3 bimetallic oxide can be considered an excellent candidate for supercapacitor electrodes. This method provides an efficient hybridization methodology for the design of high-performance electrode materials for advanced energy storage devices.