lead-acid accumulator

Show Summary Details

Quick Reference

An accumulator in which the electrodes are made of lead and the electrolyte consists of dilute sulphuric acid. The electrodes are usually cast from a lead alloy containing 7–12% of antimony (to give increased hardness and corrosion resistance) and a small amount of tin (for better casting properties). The electrodes are coated with a paste of lead(II) oxide (PbO) and finely divided lead; after insertion into the electrolyte a ‘forming’ current is passed through the cell to convert the PbO on the negative plate into a sponge of finely divided lead. On the positive plate the PbO is converted to lead(IV) oxide (PbO2). The equation for the overall reaction during discharge is:PbO2+2H2SO4+Pb → 2PbSO4+2H2O The reaction is reversed during charging. Each cell gives an e.m.f. of about 2 volts and in motor vehicles a 12-volt battery of six cells is usually used. The lead-acid battery produces 80–120 kJ per kilogram. Compare nickel-iron accumulator.

PbO2+2H2SO4+Pb → 2PbSO4+2H2O

Lead-acid accumulator

Subjects: Chemistry — Physics.

Reference entries

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.