Effect of Sn and Ca doping on the corrosion of Pb anodes in lead acid batteries

Doping with Sn and Ca is seen to improve the reversibility and charging efficiency of lead anodes used in lead acid batteries. However, one drawback of these materials is their increased corrosion rate as compared to pure lead anodes. In the present investigation, the dissolution of Pb–Sn and Pb–Sn–Ca alloys has been evaluated under different float charge conditions for extended periods of time. The float potential has been optimized based on minimum anode dissolution and oxygen evolution. Extended cycling studies show that doping with Sn maintains the reversibility of the anode. In order to minimize the weight of the anode, a small amount of Sn was coated on Pb by electrodeposition. The coated electrode reveals similar reversibility and dissolution characteristics as the Sn doped anode. Electrodeposition is seen to offer an inexpensive route for increasing the charging efficiency of Pb anodes in lead acid cells without increasing the weight of the battery.