Construction of unique cupric oxide–manganese dioxide core–shell arrays on a copper grid for high-performance supercapacitors

Abstract

Unique CuO@MnO₂ core–shell nanostructures on a copper grid have been prepared on a large scale by quick wet etching and hydrothermal deposition methods for advanced binder-free supercapacitor electrodes. The CuO@MnO₂ nanostructures are regulated and controlled on the basis of time-dependent experiments. This core–shell nanostructure displays a very high specific capacitance (343.9 F g⁻¹ at a current density of 0.25 A g⁻¹), remarkable cycling stability (83.1% retention after 12 000 cycles) and a good rate capability (70.5% of the original capacitance). These perfect electrochemical properties are attributed to synergic interaction of each component. In addition, the asymmetric supercapacitor exhibits a high energy density of 29.9 W h kg⁻¹ at a power density of 269.6 W kg⁻¹. These findings make it attractive that the CuO@MnO₂ core–shell nanostructure on a copper grid is a promising electrode material for electrochemical supercapacitors.