Alpha nickel hydroxides as lightweight nickel electrode materials for alkaline rechargeable cells

A lightweight nickel hydroxide electrode was obtained through developing a stable a-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 alpha- and beta-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 alpha-type nickel electrode to have a higher specific capacity and weight energy density than the beta-type nickel electrode. The volumetric energy density of the alpha-type nickel electrode was, however, inferior to that of the beta-type nickel electrode. Two type AA size NiMH cells were also constructed by spirally winding the alpha- and beta-type nickel electrodes and AB(5)-type MH electrodes, respectively. The cell performances were evaluated.