Gas diffusion electrode and method for its production

Abstract

A gas diffusion electrode for a PEM fuel cell includes a metallic catalyst, and an electrocatalyst layer having a polymer A for hydrophobicizing the electrocatalyst layer and a uniform thickness of between 3 to 40 μm, especially 25 μm. The polymer A content is less than 10% by weight based on the metallic catalyst content. Methods of producing and of hydrophobicizing the electrode include screen printing a paste onto a carrier and removing the screen-printing medium by heating. The paste includes at least one metallic catalyst with a content of polymer A up to at most 10% by weight, and a screen-printing medium. The electrocatalyst layer of the electrode has a significantly lower content of the catalyst inhibitor TEFLON® because it is not added only to the screen-printing paste but is subsequently applied, with the same surface-specific effect, by dipping the finished electrocatalyst layer in a solution containing TEFLON®.

Dependencies are inferred from the claim text.