ELECTROCHEMICAL SUPERCAPACITOR BEHAVIOR OF -PHASES OF NICKEL HYDROXIDE AND COBALT HYDROXIDE

Crystalline -nickel hydroxide was prepared by the addition of nickel nitrate to sodium hydroxide solution followed by ageing in mother liquor, while, -cobalt hydroxide was procured from commercial source. The electrochemical performances of -nickel hydroxide and -cobalt hydroxide was investigated using cyclic voltammetry and charge–discharge studies. A specific capacitance of 150 F g -1 was obtained in aqueous KOH in the potential range of 0 to 0.6 V (vs. Hg/HgO) for -nickel hydroxide. For cobalt hydroxide, the specific capacitance of 550 F g -1 in the potential range of -0.6 to 0.45 V (vs. Hg/HgO) was observed. The crystalline phase of -cobalt hydroxide exhibits better electrochemical supercapacitor compared to -nickel hydroxide.