Zinc Air Battery

 

Zinc air is one system that offers great promise for the future, although it is uncommon in cylindrical sizes. It is a variation of the Leclanche cell having a zinc anode but taking air from the atmosphere via a catalyst to act as the cathode. This system has a potential energy 50% greater than the alkaline battery at 1.4 volts with a flat discharge curve. The difficulties with this system are three fold: how to get sufficient oxygen from air into the cell at high rates of discharge, how to stop the liquid electrolyte seeping out through the air holes and how to stop an adverse reaction between the electrolyte and the carbon dioxide in the air.

A derivation of this is a hybrid cell half-alkaline half zinc air. A smaller proportion of manganese dioxide supports the discharge reaction in the short term and the recovery period between discharges allows the manganese dioxide to reoxidise with oxygen from the air.

Zinc air is however most commonly found in button or coin cells and, in particular, batteries used in hearing aids.