THE OXIDATION REACTION OF LEAD SULFATE FORMED AT THE INTERFACE BETWEEN THE LEAD PLATE AND THE POROUS ACTIVE MATERIAL OF A LEAD-ACID-BATTERY

Porous lead dioxide prepared on the lead substrate was discharged galvanostatically and then discharged at −450 mV from the equilibrium potential of PbO2/PbSO4 potentiostatically. The state of the interface between porous lead dioxide and the lead substrate scarcely changed after the galvanostatic discharge. On the other hand, after the following potentiostatic discharge, the large, plate-like lead sulfate crystals were formed at the interface between porous lead dioxide and the lead substrate. Then, such an electrode was oxidized potentiostatically. The oxidation current-time transients implied the existence of the electronic resistance in the electrode. Such a resistance was related to the large, plate-like lead sulfate crystals which were formed at the interface between porous lead dioxide and the lead substrate during the potentiostatic discharge. These lead sulfate crystals were not oxidizable and remained at the interface between porous lead dioxide and the lead substrate. © 1990, The Electrochemical Society, Inc. All rights reserved.