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How is antimonial lead used in battery grids and terminals?

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A periodic table element box for lead (Pb) shows atomic number 82, atomic weight 207.2, electron configuration, and labels for symbol, name, crystal structure, and physical state, with a legend for color and symbol meanings. — lead Properties of lead.

Antimonial lead, often referred to as hard lead or grid metal, is a lead alloy containing antimony, typically in concentrations ranging from 1 to 6 percent, though it can reach up to 25 percent.1

Its primary commercial application is as a cast metal for the grids and terminals of lead-acid storage batteries. The addition of antimony is essential because it significantly increases the hardness and strength of the lead, which is otherwise too soft for structural use. In battery applications, the antimony content is generally kept up to 8 percent, often supplemented with small amounts of tin, arsenic, copper, and silver to optimize performance.12

While traditional batteries rely on these antimonial lead alloys for their structural integrity, modern maintenance-free automotive batteries often utilize different compositions, such as lead-calcium alloys for the positive plates, to improve efficiency and reduce maintenance needs.1