Three-dimensional enoki mushroom-like Co3O4 hierarchitectures constructed by one-dimension nanowires for high-performance supercapacitors

In this study, we report a facile, mild and large-scale production strategy to synthesize three-dimensional (3D) enoki mushroom-like Co3O4 hierarchitectures by a simple reflux method. The structure and morphology of as-prepared products are characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. It is demonstrated that the products are 3D enoki mushroom-like Co3O4 hierarchitectures constructed by one-dimensional nanowires which are oriented and assembled in a radial form from the center to the surface of hierarchitectures. The pseudo-capacitive properties of the Co3O4 material are evaluated by cyclic voltammetry, galvanostatic charge-discharge tests and electrochemical impedance spectroscopy in 6 M KOH solution. A specific capacitance of 787 F g(-1) is obtained at a current density of 1 A g(-1). Even at a high current density of 10 A g(-1), the Co3O4 hierarchitectures maintain 94.5% and 76.6% of its initial specific capacitance after 1000 and 4000 deep cycles, respectively, which reveals comparable cycling life. It also exhibits excellent rate capability, improved energy density and power density. The excellent electrochemical performances of the Co3O4 materials could be attributed to the unique 3D enoki mushroom-like hierarchical nanostructure, which could significantly increase the work stability of the electrodes, as well as the rate for ion diffusion and electron transportation in the constructed supercapacitors. With their ease of fabrication and good performance, this 3D enoki mushroom-like hierarchitectures will hold promise for application in supercapacitors. (C) 2014 Elsevier Ltd. All rights reserved.