In Situ Hydrothermal Synthesis of Nickel Oxide Nanostructures by Thermal Decomposition and its Electrochemical Property

NiO nanorods composed of nanoparticles with diameter of 25–65 nm were synthesized on a nickel foam substrate by an in situ hydrothermal process in an aqueous solution containing only oxalic acid and subsequent calcination treatment. The nickel foam acted both as a substrate and nickel source. The calcination of the nickel foam substrate before the hydrothermal process played a crucial role in the formation of NiO nanostructures with different morphologies. Cyclic voltammetry and constant current charge–discharge measurements were used to evaluate the electrochemical properties of NiO. The results indicated a maximum specific capacitance as high as 126 F/g at a current density of 0.4 A/g.