Preparation of Gas Diffusion Electrodes with Silver Catalysts for Alkaline Fuel Cells

In alkaline fuel cells (AFC) silver can be used as the cathode catalyst in gas diffusion electrodes. To prepare the gas diffusion electrodes, the metal catalyst was mixed with polytetra-flourethylene (PTFE), as the organic binder, in a knife mill and rolled onto a metal web in a calender. The electrodes are manufactured as an endless tape with a thickness of approx. 0.4 mm and widths of up to 20 cm. Raney-silver, carbon supported silver, or silver deposited as a closed film on FLEE are used as the catalyst. In the gas diffusion electrode preparation process the silver catalyst can be used in this oxidized form. Before using the gas diffusion silver cathodes in the alkaline fuel cell the catalyst will be reduced to the metallic form.