The effect of Zn(OH)2 addition on the electrode properties of nickel hydroxide electrodes

Nickel hydroxide powders currently used in the positive electrode of nickel-metal hydride (Ni–MH) batteries require cobalt or cobalt oxides to make them viable and attractive. As a step to eliminate the cobalt-containing materials, spherical nickel hydroxide powders coprecipitated with Zn(OH)2 were prepared by a spraying technique. These powders, which have a higher tapping density and a much smaller pore volume than conventional powders, were used as the active materials of nickel hydroxide electrodes. The effects of the Zn(OH)2 additions on the electrode properties, such as percentage utilization and cycle life, were studied, and the relationship between the electrode performance and the formation of γ–NiOOH was investigated. The cycle life was increased because there was less electrode swelling due to much reduced formation of γ–NiOOH.