Electrochemical performance of nano-scale β-Ni (OH)₂ prepared at different transformations of pH value

The influence of transforming pH values on the electrochemical performance of nano-scale Ni (OH)₂ was analyzed. The measurement results of XRD indicate that the nano-scale Ni (OH)₂ prepared at different transformations of pH value is β (II)-phase with different crystal lattice parameters. Cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS) measurement results show that transformations of pH value affect the proton diffusion coefficient (D) and charge-transfer resistance (R_ct) of the material. The simulation of cell experiment shows that the sample prepared at a pH of 10.1 exhibits the maximum specific capacity (327.8 mAh/g) and higher discharge platform, the discharge performance of electrodes depends on both D and R_ct, so the kinetics characteristics that electrodes reaction is controlled by both mass-transfer step and charge-transfer step are put forward.