Studies on Corrosion Resistance and Electrochemical Behavior of Pb-Sb-As-S Alloys as Positive Grids in Lead-acid Batteries

The effects of sulfur addition in the range of 0.003-0.01wt.% on the corrosion resistance, electrochemical properties and gas evolution of Pb-Sb-As-S alloy in sulfuric acid solution were investigated by Linear sweep voltammetry, cyclic voltammetry, weight loss measurements, electrochemical impedance spectroscopy, chronoamperometry and scanning electron microscopy at room temperature. Sulfur added to lead alloy shifts the corrosion potential to negative values. Both oxygen and hydrogen evolution overpotentials were found to be higher for the alloys containing sulfur respect to samples without sulfur. The structures of low-antimony-arsenic alloy surfaces doped by sulfur were studied by using SEM. The experimental results show that, sulfur added to Pb-Sb-As alloy inhibits the growth of the anodic β-PbO2 film and increases the reaction resistance. Impedance spectroscopy measurements showed that the sulfur addition decreased the conductivity of β-PbO2 film on the lead alloy. In addition, the effect of sulfur on the hardness of the positive grids and batteries discharge capacities made of these grids was studied.