Alpha Nickel Hydroxides as Lightweight Nickel Electrode Materials for Alkaline Rechargeable Cells

A lightweight nickel hydroxide electrode was obtained through developing a stable α-phase nickel hydroxide with a 10 at. % Al substitution. The effects of an Al addition within 10−30 at. % on the interslab distance of the (001) plane as well as on the electrochemical properties were investigated. Pasted α- and β-type nickel hydroxide electrodes were fabricated to compare the specific capacity, weight, and volumetric energy densities of both types of electrodes. The results showed the α-type nickel electrode to have a higher specific capacity and weight energy density than the β-type nickel electrode. The volumetric energy density of the α-type nickel electrode was, however, inferior to that of the β-type nickel electrode. Two type AA size NiMH cells were also constructed by spirally winding the α- and β-type nickel electrodes and AB 5 -type MH electrodes, respectively. The cell performances were evaluated.