Contribution à l’étude du rôle de l’eau de structure dans le mécanisme de formation de α-PbO2.

Abstract

The cured plate of lead/acid battery consists of tribasic lead sulfate (3BS), (α + β) PbO and monobasic lead sulfate (1BS). We found that during plates soaking before formation in H2SO4 respectively with 1.05 and 1.20 g.cm-3 specific gravity, affects the stability of 3BS and PbO which are converted to monobasic lead sulfate (1BS) and PbSO4. The thermal decomposition of the paste showed a decrease in the amount of structural water and energy of dehydration. During formation of the paste all compounds of the cured paste are converted to PbO2 with differents amounts of α and β PbO2. 3BS is transformed to α PbO2 while PbSO4 leads to the β PbO2 form. The capacity and cycle life of the PAM decrease with increasing of acid concentration soaking time. PAM prepared by oxidation of PbSO4 is significantly influenced by the pH of the electrolyte. The phase composition, average crystallite size and capacity of PAM are modified.