Patent ID: 8293806

Claim:
A membrane electrode unit comprising: (I) at least one electrode and (II) at least one proton-conducting polymer membrane based on polyazoles obtained by a process comprising the steps: A) dissolving a polyazole polymer in polyphosphoric acid to form a solution, B) heating the solution obtained as described in step A) to temperatures of up to 400° C., under inert gas, C) formulating a membrane on a support using the solution of the polyazole polymer from step B), and D) treating the membrane formed in step C) by partially hydrolyzing the polyphosphoric acid in the presence of moisture at temperatures and for a time which are sufficient for the membrane to become self-supporting so that it can be detached from the support without damage, and wherein the polyphosphoric acid used in step A) has an assay calculated as P 2 0 5 (acidimetric) of at least 85% and said membrane has a conductivity of at least 0.1 S/cm at a temperature of 120° C.