THE PLATE MATERIALS OF THE LEAD-ACID CELL. PART II. ANODIC OXIDATION OF PBSO4, PB3SO4, 2PBCO3.PB(OH)2, AND ORTHORHOMBIC PBO.

Four compounds commonly present in the active material pastes of the lead-acid cell PbSO4, Pb3O4, 2PbCO3 . PbOH2, and orthorhombic PbO were individually oxidized anodically in dilute sulfuric acid. X-ray diffraction showed that each transformed to beta PbO2. The anodic products were examined in the electron microscope directly and by means of carbon replicas. Lead sulfate and 2PbCO3 . PbOH2 formed primarily complex dendritic crystals of PbO2 Pb3O4 gave rise to clusters of prismatic tabular crystals and nondescript nodules and orthorhombic PbO was transformed to agglomerates of nondescript particles showing no evidence of prismatic dendritic crystallization. These forms of crystallization are compared with those observed in commercial battery plates including lead-calcium cells giving satisfactory and unsatisfactory float performance. The morphologies of the PbO2 particles resulting from the electrochemical transformations depended upon the source material, and their probable growth mechanisms are discussed. Author