Study of passivation at the positive active material/grid interface in lead-acid batteries

A valuable additive - boric acid - to eliminate passivation of the active m aterial/grid interface in positive plates of lead-acid batteries has been s elected through comparison of single-cell discharge tests. This overcomes t he problem of rapid decline in initial performance when using low-antimony (1.7 wt.%) grid alloys. The performance of the oxide film on positive grids , as well as its composition and amount, is determined through cathodic red uction of the film with a linear sweep voltammetric (LSV) method. The resul ts confirm that passivation of the positive grid and rapid decline in the i nitial discharge voltage are due to a resistive layer of PbSO4, and not PbO n, (1 less than or equal to n less than or equal to 2). The PbOn layer has little effect on passivation. The findings of this study are useful for the production of lead-acid batteries. (C) 2000 Elsevier Science S.A. All righ ts reserved.