Preparation and performance of lead foam grid for negative electrode of VRLA battery

Lead (alloy) foam was prepared via electrodeposition by using copper foam as the substrate and adding element cerium to the electrodepositing solution under ultrasonic treatment. The performances and morphology of the lead foam were investigated by means of SEM and AFM. The results show that because of the addition of cerium and the application of ultrasound, the distribution thickness ratio (DTR) of the lead foam is decreased. The lead foam has a uniform three-dimensional reticulate structure with a specific surface area of about 5700 m(2) m(-3), a porosity of about 88.1%, and an apparent resistivity of about 150 mu Omega cm(-1). The results of the cyclic voltammetry indicate that the lead foam has a good stability when it is used as the negative electrode material of a lead acid battery. The battery testing revealed that, at 5, 2 It and high current discharge rates, there are improvements of 28.5%, 29.5% and 20.4% in the negative active material utilization efficiencies with the lead-foam VRLAB compared with the cast grid one and the mass specific capacities of the lead foam negative electrode are 36%, 44% and 33% higher than those of the cast grid one. (c) 2005 Elsevier B.V. All rights reserved.