Nickel oxide/hydroxide nanoplatelets synthesized by chemical precipitation for electrochemical capacitors

摘要

Nickel hydroxide powder prepared by directly chemical precipitation method at room temperature has a nanoplatelet-like morphology and could be converted into nickel oxide at annealing temperature higher than 300 ℃, confirmed by the thermal gravimetric analysis and X-ray diffraction. Annealing temperature influences significantly both the electrical conductivity and the specific surface area of nickel oxide/hydroxide powder, and consequently determines the capacitor behavior. Electrochemical capacitive behavior of the synthesized nickel hydroxide/oxide film is investigated by cyclic voltammetry and electrochemical impedance spectroscope methods. After 300 ℃ annealing, the highest specific capacitance of 108 F g{sup}(-1) is obtained at scan rate of 10 mV s{sup}(-1). When annealing temperature is lower than 300 ℃, the electrical conductivity of nickel hydroxide dominates primarily the capacitive behavior. When annealing temperature is higher than 300 ℃, both electrical conductivity and specific surface area of the nickel oxide dominate the capacitive behavior.