Construction of Three-Dimensional Homogeneous NiCo2O4 Core/Shell Nanostructure as High-Performance Electrodes for Supercapacitors

A novel three-dimensional homogeneous NiCo2O4 core/shell nanowire arrays were first fabricated via a facile synthesis strategy on nickel foam as advanced binder-free electrodes. The structure and morphology of the as-synthesized samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray spectrometry (EDS) and transmission electron microscopy (TEM). This novel NiCo2O4/NiCo2O4 core/shell nanowire arrays exhibited superior electrochemical performances, including high specific capacitance of 2041 F g(-1) at current density of 5 mA cm(-2), excellent rate performance with a capacitance retention of 88% as the current density increases from 5 to 50 mA cm(-2) and good long-term cyclic stability. These outstanding electrochemical characteristics are mainly attributed to the superstructure, which provides a large number of electroactive sites for redox reaction, shortens the ion diffusion paths and enhances the morphological stability in the electrochemical process. (C) The Author(s) 2015. Published by ECS. All rights reserved.