Effects of ultrasonic treatment on the structure and electrochemical performances of spherical β-Ni(OH)2

A method of ultrasonic treatment (UST) was first used to modify the structure and electrochemical performance of nickel hydroxide for the active material of nickel series alkaline batteries. The experimental results showed that UST was an effective method to improve the electrochemical performance of beta-Ni(OH)(2) such as specific discharge capacity, discharge potential, electrochemical reversibility and oxygen evolution over-potential. The results of electrochernical impedance spectroscopy, powder X-ray diffraction and particle size distribution indicated that the improvement of the performance of beta-Ni(OH)(2) through LIST was attributed to the reduction of the charge-transfer resistance (R) and the diffusion impedance (Z(w)), which resulted from the decrease of the crystallite and particle size and the increase of interlayer spacing. Diffusion coefficient of proton D-H of ultrasonic treated beta-Ni(OH)(2) gained by CV tests was 1.13 X 10(-11) cm(2)/s, and the average discharge specific capacity of ultrasonic treated beta-Ni(OH)(2) electrode was 301 mAh/g.