Charging oxygen recombination

To prevent the dimerization and by-product formations, Rautenstrauch et al. (1981) proposed to protonate the ketone anion-radicals just at the moment of their formation. These anion-radicals contain the negatively charged oxygen atom. They protonate faster and then undergo dimerization. The resulting hydroxyl-containing carboradicals accept electrons faster and then undergo disproportionation or recombination. This leads to the suppression of ketoenol and pinacol formation. 

As pointed out in the preceding reviews of separator function and separator materials (Chapters 6 and 7, respectively) and of charging strategies (Chapter 9), the separator plays a crucial role in VRLA cells. Provision of a separator with the appropriate microstructure can constrain the rate of oxygen arrival at the negative plate and thus restrict the suppression of the plate potential caused by the oxygen-recombination reaction. 

Sealed lead-acid batteries are in both cylindrical and prismatic shapes. The cyclindrical ones (usually designed as SLA batteries) have excellent high-rate characteristics. Other than in portable devices, sealed batteries can be used in standby applications, e.g. telephone exchange stations, were they are kept in float charge. In this case too, oxygen recombination is possible. 

In the sealed cell, an oxygen recombination reaction occurs during charge. At the positive electrode, oxygen is evolved ... 

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