PbO2 Lead oxide

Therefore, passivation of the positive electrode by poorly conducting PbSO4 can be reduced [348]. The porosity is important because it enables the expansion during the solid phase volume increase, which accompanies the transformation of PbO2 to PbSO4. Ill the most popular construction, the electrode paste material (mixture of metallic lead with lead oxides) is held in a framework composed of lead alloys with additions of tin, antimony, selenium, and calcium 1348]. Antimony improves the mechanical stability however, it increases the resistance and facilitates the selfdischarge of the battery. Better results are obtained for low antimony content and/or for lead-calcium alloys [203]. Methods of positive elec trodes improvement, from the point of view of lead oxide technology have been discussed [350]. Influence of different factors on life cycle, nature, and composition of the positive active mass has been studied by Pavlov with coworkers [200, 351, 352]. 

The oxidation of lead in various electrolyte solutions has been studied [736-738]. In a tetraborate solution, the photocurrent spectrum measured with white light showed a marked dependence on the positive (anodic) potential limit of the potential scans. With the most positive limit, the photocurrent-potential relationship displayed in Fig. 5.128 was obtained. The formation of tetragonal PbO by reduction of 0 -PbO2 was monitored. The onset of the photocurrent indicates the appearance of the formation of PbO and the electrode potential coincides with the sudden onset of the photocurrent in the anodic scan. In the positive-going scan, the photocur-... 

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