PREPARATION AND ELECTROCHEMICAL PERFORMANCE OF COBALT HYDROXIDE AND NICKEL HYDROXIDE COMPOSITE MATERIALS

Transition metal oxides(hydroxides) have great concern due to its excellent capacitance characteristics, in which Co(OH)₂ and Ni(OH)₂ research is a hot spot. Different molar ratios of Co(OH)₂/Ni(OH)₂ composite materials are prepared by electrochemical deposition, characterization of the morphology and the structure of deposited product is carried out by means of XRD and SEM, electrochemical properties are performed by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The results show that:different molar ratios of Co(OH)₂/Ni(OH)₂ composite materials can be prepared by electrochemical deposition method, electrode materials possess nano-flower structure, this structure greatly increases the specific surface area of active materials. With increase of Co(NO₃)₂ or Ni(NO₃)₂ content in the electrolyte solution, Co(OH)₂/Ni(OH)₂ electrode materials discharge time and specific capacitance value show a trend of first increase and then decrease. Among them, when Ni(NO₃)₂:Co(NO₃)₂=1:1, Co(OH)₂/Ni(OH)₂ composite material deposited possesses the longest discharge time and the biggest specific capacitance, the specific capacitance value is as high as 841.15 F/g.