Preparation and electrochemical properties of nickel oxide by molten-salt synthesis

Well-crystallized NiO nanoparticles with uniform morphology of hexagon plates were first fabricated by molten-salt synthesis method using NaCl as a flux at 1000 degrees C. The phase of the synthesized NiO powder was confirmed by comparing the obtained XRD pattern with the JCPDS standard. Transmission electron microscopy (TEM) image shows that the morphology of NiO particle is hexagon plate with particle size of 50-80 nm. NiO nanoparticles prepared by molten-salt synthesis method is homogenous and in high purity. The NiO sample has a better particle size distribution than that obtained from liquid precipitation and solid state reaction. The electrochemical behavior was investigated by chronopotentiometry and electrochemical impedance spectroscopy. The nickel oxide sample calcined at 1000 degrees C exhibited electrochemical supercapacitive behavior. The internal resistance measured at open circuit potential is only 0.5 Omega, which is smaller than that of the NiO prepared by other conventional precipitation. NiO prepared by molten-salt synthesis is a potential electrode material for supercapacitor. (C) 2007 Elsevier B.V. All rights reserved.