Hierarchical Co3O4 nanosheet@nanowire arrays with enhanced pseudocapacitive performance

Electrodes with hierarchical nanoarchitectures could offer many opportunities for improved performance in energy storage. Herein, we report the synthesis of a hierarchical Co3O4 nanosheet@nanowire arrays (NSWAs) by a facile hydrothermal and annealing treatment. The synthesis of Co3O4 NSWAs, composed of Co3O4 nanowires standing on nanosheet arrays, was achieved in two steps. The formation of nanosheet arrays on nickel foam and the growth of the nanowires around the sheets in the form of nanowires was achieved by studying the morphology evolution process upon reaction time. This novel structure of the material provides a high specific capacitance of 715 F g(-1) and remarkable rate capability (at least 69% can be maintained when the current density increased 6 times). Furthermore, the excellent cycling performance (100% after 1000 cycles) is another essential factor in making the Co3O4 hierarchical NSWAs an advanced supercapacitor material.