Influence of antimony ions and PbSO sub 4 content in the corrosion layer on the properties of the grid/active mass interface in positive lead-acid battery plates

Antimony in lead/antimony alloys is known to have a beneficial influence on the capacity and cycle life of lead-acid battery positive plates. The present work shows that Sb sub 3 O sub 9 exp 3- ions formed on oxidation of PbSb alloys improve the capacity of the Pb/PbO sub 2 electrode, while SbOSO sub 4 exp - ions have an adverse effect and passivate this electrode. A mechanism of the influence of these ions is proposed based on the gel-crystal concept for the structure of PbO sub 2 . The paper also discusses the effect of PbSO sub 4 formed at the grid/PAM interface on the capacity. It has been established that the major part of the PbSO sub 4 crystals are oxidized to PbO sub 2 within a few cycles. There still remain a certain number of PbSO sub 4 crystals which border narrow pores and are oxidized at a very slow rate, thus preserving their influence even after ten discharge-charge cycles. It has also been found that the higher the density of PAM the stronger the adverse effect of PbSO sub 4 in the grid/PAM interface on the capacity. All these phenomena are related to the PCL effect and methods to suppress them are proposed.