Nanocrystalline NiO was synthesized by a simple liquid-phase process. Thermogravimetric and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD) and transmission electron microscope (TEM) tests were applied to investigate the thermal behavior, morphology and crystalline of the NiO powders. Electrochemical properties of NiO crystalline were examined by cyclic voltammetry. A specific capacitance approximately to 300 F g could be achieved with NiO crystalline in the range of 0.0-0.5 V. (C) 2003 Elsevier B.V. All rights reserved.