GAS DIFFUSION ELECTRODE AND PROCESS FOR PRODUCING IT AND ITS USE

摘要

The invention describes a process for producing a gas diffusion electrode which has a catalyst layer having a smooth surface, wherein the smooth surface of the catalyst layer is produced by bringing the catalyst layer in the moist state into contact with a transfer film and removing this transfer film after drying. In variant A, the catalyst layer is firstly produced on a transfer film and then transferred in the moist state to the gas diffusion layer. In variant B, the catalyst layer is applied to the gas diffusion layer, and a transfer film is then placed on top. In both cases, the structure produced in this way is subsequently dried. Before further processing, the transfer film is removed to give a gas diffusion electrode having a smooth catalyst surface which has a maximum profile peak height (Rp) of less than 25 microns. The electrodes are used for producing membrane-electrode assemblies for membrane fuel cells or other electrochemical devices. Membrane-electrode assemblies comprising the gas diffusion electrodes of the invention display very good long-term behaviour.