The aim of this study was to compare the electrochemical corrosion behavior of as-cast Pb–1wt% Sn and Pb–2.5wt% Sn alloy samples in a 0.5M H2SO4 solution at 25°C. A water-cooled unidirectional solidification system was used to obtain the as-cast samples. Electrochemical impedance spectroscopy (EIS) diagrams, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the electrochemical corrosion response. It was found that a coarse cellular array has a better electrochemical corrosion resistance than fine cells. The pre-programming of microstructure cell size of Pb–Sn alloys can be used as an alternative way to produce as-cast components of lead-acid batteries with higher corrosion resistance associated with environmental and economical aspects.