Construction of hierarchical ZnCo2O4@NixCo2x(OH)6x core/shell nanowire arrays for high-performance supercapacitors

Rational design and synthesis of core/shell nanostructures as binder-free electrodes has been believed to be an effective strategy to improve the electrochemical performance of supercapacitors. In this work, hierarchical ZnCo2O4@NixCo2x(OH)(6x) core/shell nanowire arrays (NWAs) have been successfully constructed by electrodepositing NixCo2x(OH)(6x) nanosheets onto hydrothermally grown ZnCo2O4 nanowires and investigated as a battery-type electrode for hybrid supercapacitors. Taking advantage of the hierarchical core/shell structures and the synergetic effect between ZnCo2O4 nanowires and NixCo2x(OH)(6x) nanosheets, the optimised core/shell electrode exhibits remarkable electrochemical performance with a high areal capacity (419.1 mu A h cm(2)), good rate capability and cycling stability. Moreover, the assembled ZnCo2O4@NixCo2x(OH)(6x)//activated carbon (AC) hybrid device can be reversibly cycled in a large potential range of 0-1.7 V and deliver a maximum energy density of 26.2 W h kg(-1) at 511.8 W kg(-1). Our findings indicate that the hierarchical ZnCo2O4@NixCo2x(OH)(6x) core/shell NWAs have great potential for applications in energy storage devices.