Coprecipitation fabrication and electrochemical performances of coral-like mesoporous NiO nanobars

Abstract

A simple and template-free coprecipitation method using Na₂O₂ aqueous solution as the OH⁻ source has been developed to synthesize coral-like mesoporous NiO nanobar precursors, which were then transformed to NiO by a simple calcination procedure. The fabricated NiO nanomaterials have a relatively high specific surface area and porous structure, making them ideal candidates for pseudocapacitor applications. The pseudocapacitive properties of the as-prepared NiO electrodes have been examined by cyclic voltammetry (CV), cyclic chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) in 6.0 M KOH solution. A high specific capacitance (SC) of 1085 F g⁻¹ with an excellent energy density of 30.52 W h kg⁻¹ could be obtained at a discharge current density of 1 A g⁻¹. And the as-prepared NiO electrode also exhibits good long-term cycling stability at a high current density of 5 A g⁻¹.