Synthesis of hierarchical porous NiO nanotube arrays for supercapacitor application

Abstract Tailor-made porous nanotube arrays are of great technological interest for the development of high-performance optical and electrochemical energy storage devices. Herein, we report facile successive electro-deposition (ED) methods to fabricate three-dimensional (3D) hierarchical porous NiO nanotube arrays on nickel foam with the help of ZnO nanorod template. The obtained hierarchical porous NiO nanotubes have a diameter of ∼170 nm and consist of interconnected branch nanoflakes of ∼10 nm. The resulting NiO nanotube arrays are well characterized as positive electrode materials for supercapacitor application by cyclic voltammetry (CV) and galvanostatic charge/discharge measurements. Due to the unique architecture, the NiO nanotube arrays exhibit a high capacitance of 675 F g−1 at the 2 A g−1 and 569 F g−1 at 40 A g−1, respectively, as well as good cycling stability. The proposed synthesis method is expected for fabrication of other nanotube arrays for applications in solar cells, gas sensors and Li ion batteries.