The effect of barium sulfate-doped lead oxide as a positive active material on the performance of lead acid batteries

Abstract

Barium sulfate (BaSO₄) is a common impurity in recycled lead paste that is challenging to eliminate completely during hydrometallurgical recycling of spent lead acid batteries, so the effect of this impurity in positive active materials on the performance of recycled lead acid batteries was investigated. The BaSO₄ doped lead oxide composite was used as a positive active material in positive plates of lead acid batteries with theoretical capacities of 2.0 A h. BaSO₄ was retained in the solid phase throughout the battery fabrication process. Different BaSO₄ dosages affected the phase of the positive plates during the curing process, with the highest content of metallic lead obtained at a BaSO₄ dosage of 0.06 wt%. Morphology analysis indicated that aggregates were formed in the positive plates and the particles became rougher with increasing addition of BaSO₄ during the formation process. BaSO₄ also demonstrated a large impact on charge/discharge cycles with 100% DOD in battery testing. Analysis of disassembled failed batteries indicated that the expansion and shedding-off of the positive active material were mainly responsible for the failure of these batteries, and this could be attributed to the non-uniform growth of lead oxide on the BaSO₄ nucleus, and the accumulation of internal stress.