Primary zinc air cell - with oxygen reduction activating layer and hydrophobic layer forming the positive air electrode

摘要

A primary galvanic cell with an alkaline electrolyte includes a negative electrode (zinc) and a positive air electrode. The latter consists of the electrolyte side of a layer which activates the oxygen reduction and, firmly connected it a hydrophobic layer on the gas side. The hydrophobic layer is pref. a thermoplastic material such as PTFE. Its thickness can vary between 25 and 100 mu and it has a permeability factor for air from 10-8 and 10-5cm3/cm.s.bar. The electrolyte pref. is caustic soda soln. A metallic bleeder grid is embedded in the layer for the activation of the oxygen reduction. Such a cell can supply small currents of up to a few 100mA over long working and periods so that it ideal for button cells required in wristwatches or pocket computers.