Stabilized α ‐ Ni (  OH  ) 2 as Electrode Material for Alkaline Secondary Cells

Hydrotalcite‐like compounds of formula Ni 1 − x Al x ( OH ) 2 ( CO 3 ) x / 2 · n H 2 O ( x = 0.1 to 0.25 ) , having the same structure as that of α ‐ Ni ( OH ) 2 , have been synthesized by substituting nickel hydroxide with aluminum. Of these, the compounds of compositions x ≥ 0.2 are found to have prolonged stability in strong alkaline medium. The electrodes comprising stabilized α ‐ Ni ( OH ) 2 of x = 0.2 composition are rechargeable with discharge‐capacity values of 240 (±15) mAh‐g −1 and are attractive for applications in various alkaline secondary cells employing nickel‐positive electrodes.