Shintaro Ishida

Preparation and Characterization of Ni/Al‐Layered Double Hydroxide

The electrochemical behavior of chemically prepared α-phase Al-substituted Ni(OH) 2 was investigated in relation to its crystallinity. α-Phase samples with 5-20% Al were prepared by precipitation, and the crystallinity was tailored by changing the metal/alkali ratio or the aging temperature. A highly crystallized sample was obtained without controlling the reaction pH. Both the utilization and half-discharge potential increased as the sample crystallinity improved. A maximum capacity of 381 mAh/g and utilization of 190% were obtained. The crystallinity dependence of the cell performance was explained by the reduction of polarization because of a more ordered structure which led to a faster solid-state reaction.