Proton-conducting membrane and the use of the same

A process to produce proton-conducting polymer membrane based on polyazoles 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) 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.

An electrode provided with a proton-conducting polymer coating based on polyazoles which has a concentration of phosphoric acid expressed as mol of acid per mol of recurring unit of the polymer of from 12 to 20 which membrane is 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) applying a layer to an electrode using the solution of the polyazole polymer from step B), and.
• D) treating the layer formed in step C) at temperatures of from 0° C. to 150° C. in the presence of moisture.

A membrane-electrode unit comprising:

• at least one electrode provided with a proton-conducting polymer coating based on polyazoles which has a concentration of phosphoric acid expressed as mol of acid per mol of recurring unit of the polymer of from 12 to 20 which membrane is obtained by a process comprising the steps
• i) dissolving a polyazole polymer in polyphosphoric acid to form a solution,
• ii) heating the solution obtained as described in step i) to temperatures of up to 400° C., under inert gas,
• iii) applying a layer to an electrode using the solution of the polyazole polymer from step ii), and
• iv) treating the layer formed in step iii) at temperatures of from 0° C. to 150° C. in the presence of moisture;
• and
• at least one proton-conducting polymer membrane based on polyazoles which has a concentration of phosphoric acid expressed as mol of acid per mol of recurring unit of the polymer of from 12 to 20 and is 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 of the membrane formed in step C) 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.