Preparation of nanospherical porous NiO by a hard template route and its supercapacitor application

Abstract

A nanospherical porous NiO electrode material was successfully prepared by a nanocasting method using porous carbon nanospheres as a hard template. The obtained porous NiO materials were characterized with high crystalline degree, larger surface area than 200m2g-1, 5–6nm mesoporous channels and nanospherical morphology with 500–700nm in diameter, which render them excellent electrochemical performance. The galvanostatic charge–discharge measurements demonstrated that the optimal electrode possessed a high specific capacitance of 1201Fg−1 at a discharge current density of 0.5Ag−1. In addition, specific capacitances at different discharge current densities indicated a good capacitance at high current density and electrochemical impedance spectra suggested low charge transfer resistance of the electrodes. It also exhibited cycling stability of 70% capacity retention after 500 continuous charge/discharge cycles.