Abstract: Nano-sized nickel oxide（NiO） was synthesized by low temperature solid-state method.The structure and morphology of NiO and its electrochemical performance as electrode material for use in supercapacitor were studied under different thermal treatment conditions.The product′s structural features were investigated by XRD  and SEM，and its electrochemical performance was characterized by cyclic voltammetry and galvanostastic charge-discharge method etc..Results of XRD indicated that the synthesized NiO was cubic phase and the crystal tended to be complete with the increasing temperature of heat treatment.Results of SEM and electrochemical tests showed that high temperature（>400 ℃） made a more serious conglomeration， resulting in low utilization ratio of electrode material，high resistance of proton transfer and sharply decreasing of specific capacitance; NiO particles distributed more uniformly by low temperature thermal treatment with the pore passage for the electrolyte permeation， which made electrode had high specific capacitance（228 F/g） and superior electrochemical cycling stability.Additionally it also retained a good rate performance at a scan rate of 20 mV/s.

Key words: nano-sized nickel oxide, supercapacitor, thermal treatment