Comparison of Pb-Sm-Sn and Pb-Ca-Sn alloys for the positive grids in a lead acid battery

The anodic behavior of Pb-0.73 wt.% Sm-0.63 wt.% Sn and Pb-0.088 wt.% Ca-0.63 wt.% Sn alloys in sulfuric acid solution has been studied using linear sweep voltammetry, impedance-time curves and cyclic voltammetry. The experimental results show that the samarium in the Pb-Sm-Sn alloy can inhibit the growth of the anodic corrosion layer (PbO2) formed on the alloy. Moreover, the rate of the oxygen evolution at the Pb-Sm-Sn alloy electrode is lower than that at the Pb-Ca-Sn alloy electrode. 2V-200Ah VRLA batteries were separately manufactured using the Pb-Sm-Sn and Pb-Ca-Sn positive grids. The results of the test show that the capacity loss of the battery with the Pb-Sm-Sn positive grids is significantly less than that of the battery with the Pb-Ca-Sn positive grids. © 2003 Elsevier B.V. All rights reserved.