A sealed lead-acid cell or battery includes positive plates made from an alloy consisting essentially of lead, from about 0.025% to about 0.06% calcium, from about 0.3% to about 0.9% tin, and from about 0.015% to about 0.045% silver. ...http://www.google.es/patents/US5691087?utm_source=gb-gplus-sharePatente US5691087 - Sealed lead-acid cells and batteries
