Mesoporous ITO/NiO with a core/shell structure for supercapacitors

In this study, a novel mesoporous NiO/ITO NW with a shell/core structure has been successfully synthesized by combining chemical vapor deposition (CVD) on titanium substrate and electrodeposition of H-l-e (hexagonal lyotropic) nickel hydroxide through a lyotropic liquid crystalline (LLC) template, followed by calcination in air at 270 degrees C. The electrode material is characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Both cyclic voltammetry (CV) and chronopotentiometry demonstrate enhanced electrochemical properties of NiO/ITO NWs composite electrode and improved supercapacitive behaviors as compared to bulk mesoporous nickel oxide film. Maximum specific capacitance of 1025 F g(-1) at a discharge current density of 1 A g(-1) in the potential ranges from 0 V to 0.5 V is determined by galvanostatic charge-discharge measurement in 1 M KOH solution. The newly synthesized heterostructure also possesses high capacitance retention ratio at high discharge current densities and long-term electrochemical stability in an alkaline solution. Therefore, this study provides a promising electrode engineering technique for various applications. (C) 2013 Elsevier Ltd. All rights reserved.