THE PBO2 PARTICLE - EXCHANGE-REACTIONS BETWEEN IONS OF THE ELECTROLYTE AND THE PBO2 PARTICLES OF THE LEAD-ACID-BATTERY POSITIVE ACTIVE MASS

Two types of PbO2 active material from positive battery plates and a PbO2 reagent obtained by chemical methods were investigated. The first type of PbO2 active material was obtained from battery plates pasted with 4PbO . PbSO4 paste and the second type from plates pasted with 3PbO . PbSO4 . H2O. The battery plates were washed from the H2SO4 solution and dried, then the active material was removed from the grids and dispersed into powder. The obtained PbO2 powder was subjected to analysis. Through transmission electron microscopy and electron diffraction analysis it was established that PbO2 particles comprise zones with the structure of beta-PbO2, and amorphous zones containing bonded water (lead hydroxide). On heating the PbO2 Particles inside the microscope, evaporation of water from the particles was observed. Through x-ray diffraction analysis the changes in crystallinity of the PbO2 Particles as a result of their interaction with ions of the solution were investigated. Since no redox processes were registered in the PbO2 Particles for the time of the experiment, the change in crystallinity of the active material was assigned only to changes in the ratio between the crystal and amorphous zones in the particles. It was established that hydrated zones exchange H+ and OH- ions with ions of the solution. Hence, it was concluded that hydrated zones exhibit an amphoteric character. This indicates that PbO2 particles are open systems which react adequately to any change in the ion content of the surrounding solution.