Fabrication of hierarchical core/shell MgCo(2)O(4)@MnO(2) nanowall arrays on Ni-foam as high–rate electrodes for asymmetric supercapacitors

Design and fabrication of a hierarchical core/shell MgCo(2)O(4)@MnO(2) nanowall arrays on Ni-foam by a facile two-step hydrothermal method. The electrochemical measurements prove these composites with MnO(2) definitely offer better supercapacitive performance of the MgCo(2)O(4) electrode material. The nanowall structure provides more active sites and charge transfer during the Faradic reaction. The MgCo(2)O(4)@MnO(2) nanowall shows an excellent electrochemical performance (852.5 F g(−1) at 1 A g(−1)). The asymmetric supercapacitor is composed of the MgCo(2)O(4)@MnO(2) nanowall and the activated carbon (AC). The energy densities of the asymmetric supercapacitor device can keep up 67.2 Wh·kg(−1) at 5760.0 W·kg(−1). The MgCo(2)O(4)@MnO(2) nanowall shows excellent supercapacitive performance and has a great potential for more research and application in the asymmetric supercapacitor devices field.