The Influence of Antimony, Tin, and Phosphoric Acid

Antimony (Sb) and tin (Sn) are usually not added to the active material, but both are alloying components of the grid. They are gradually released from the grid by corrosion, and permeate the active material by dissolution and diffusion. 

When specimens of pure lead and a 5% antimony alloy were periodically oxidized and reduced, lead oxide layers were observed with different structures  

The origin of such insulating layers may explain the high resistance also established within the active material when antimony is not present. 

The Kugelhaufen model mentioned in the preceding section explains the beneficial influence of antimony by improved conductivity of the zones that connect the spheres. According to the gel model, antimony decreases the crystallinity of Pb02 and so increases the conductivity by the gel zones [41], and especially influences 

Jurgen O. Besenhard copyrright O WILEY-VCH Verlag GmbH,l9W 

(1955) Storage Batteries, John Wiley Sons, Inc. New York, p. 2ff. 

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