Hierarchical mesoporous NiCo2O4@MnO2 core–shell nanowire arrays on nickel foam for aqueous asymmetric supercapacitors

Abstract

We demonstrate the design and fabrication of hierarchical mesoporous NiCo₂O₄@MnO₂ core–shell nanowire arrays on nickel foam via a facile hydrothermal and electrodeposition process for supercapacitor applications. In order to increase the energy density and voltage window, a high-voltage asymmetric supercapacitor based on hierarchical mesoporous NiCo₂O₄@MnO₂ core–shell nanowire arrays on nickel foam as the positive electrode and activated carbon (AC) as the negative electrode was successfully fabricated. The as-fabricated asymmetric supercapacitor device achieved a specific capacitance of 112 F g⁻¹ at a current density of 1 mA cm⁻² with a stable operational voltage of 1.5 V and a maximum energy density of 35 W h kg⁻¹. The present NiCo₂O₄@MnO₂ core–shell nanowire arrays with remarkable electrochemical properties could be considered as potential electrode materials for next generation supercapacitors in high energy density storage systems.