The preparation and electrochemical performance of α-Ni(OH)2 with different Al contents

In this paper, alpha-Ni(OH)(2) with different Al contents was prepared by a homogeneous precipitation method. The microstructure was characterized by FT-IR and XRD, and the composition of the samples was analyzed with inductive coupled plasma (ICP). Galvanostatic charge-discharge, cyclic voltammetry and impedance spectroscopy were used to measure the electrochemical behavior of samples. Results show that the stable alpha-Ni(OH)(2) phase can be obtained for the samples with Al contents in the range of 5wt%-20wt% by the homogeneous precipitation method. And the alkali salt with the same structure as alpha-Ni(OH)(2) is obtained without Al addition. According to ICP, there is big difference between the Al contents in the practical solution and the addition, and this difference increases with the decrease of Al addition contents. The specific capacity of discharge increases first, then decreases with the Al contents decreasing, and the charge potential decreases first, then increases. The discharge potential changes little first, then decreases promptly. For the samples with Al contents in the range of 5wt%similar to 20wt%, the diffraction peaks move towards high diffraction angle after cycled for 50 times. However, the alpha-Ni(OH)(2) structure still remains. The sample without Al addition transforms into alpha-Ni(OH)(2) after cycling 50 times and the structure is destroyed heavily.