Structure and Electrochemical Performance of Al and Y Co-Doped α-Nickel Hydroxide as a Cathode for a Ni-MH Battery

The Al and Y elements co-doped α-Ni(OH)2 materials were prepared by a chemical complexing precipitation method. The physical properties and structures of these materials were characterized, and their electrochemical performance as a cathode for Ni-MH batteries was measured. The results show that Al and Y elements partially replaced Ni atoms in the layers and attracted more anions between interlayers, thereby neutralizing the positive charge and stabilizing the structure. Therefore, the Al and Y elements co-doped α-Ni(OH)2 cathode displays excellent reaction reversibility, low electrochemical resistance, and fast diffusion rate. Besides, the cycling stability indicates that the discharge capacity and the activation rate are improved by adding Y element. The sample containing 2 atom % Y has the highest capacity of 388 mAh g–1 at 1 C rate, and it has great rate performance and great cycle stability. This is a promising material as a cathode applied in Ni-MH batteries.