CHARACTERIZATION OF NEW NICKEL HYDROXIDES DURING THE TRANSFORMATION OF ALPHA-NI(OH)(2) TO BETA-NI(OH)(2) BY AGING

The aim of this paper is to characterise the compounds formed by the a geing of alpha NI(OH)(2) in 5 M KOH at 70 degrees C. The final product of this treatment is known as the beta Ni(OH)(2) phase, but with the ageing period, a progressive change of electrochemical reactivity as w ell as a textural and structural evolution are observed. The products obtained are stable in time once the ageing is stopped and are not a m ere mixture of alpha and beta but single phase nickel hydroxides whose properties are intermediate between those of alpha and beta Ni (OH)(2 ). Intermediate forms of nickel hydroxide, whose specific features see m to be the crystallites size and the quantity of absorbed nitrate ion s, will be called ''badly crystallised beta'' or beta(bc) as proposed by Delmas et al.