Granted Patent B2

US 7,220,510 · App. 10/956,653 · Granted May 22, 2007

Abstract

Claims (37)

1. A polyelectrolyte membrane suitable for use in a fuel cell, comprising a solid state sulfonation product of a fluorinated polymer in film form, wherein the fluorinated polymer comprises repeating units represented by the structure

wherein Ar1 and Ar2 are independently selected from the group consisting of aryl ring, aryl ring system, and thiophene, and are optionally substituted with C 1 to C 4 alkyl groups.

2. A membrane, according to claim 1 , wherein Ar1 and Ar2 comprise phenyl rings.

3. A membrane according to claim 1 , wherein Ar1 comprises a thiophene ring.

4. A membrane according to claim 1 , wherein Ar1 comprises a thiophene ring and Ar2 comprises a phenyl ring.

5. A membrane according to claim 1 , made by a process comprising reacting a film of the fluorinated polymer with a sulfonating agent.

6. A membrane according to claim 5 , wherein the sulfonating agent comprises chlorosulfonic acid.

7. A membrane according to claim 1 , wherein the ion exchange capacity of the membrane is from about 0.5 to about 3.2 meq SO 3 H/g.

8. A fuel cell comprising a polyelectrolyte membrane according to claim 1 .

9. A method for making a polyelectrolyte film comprising

reacting an arylene polymer with a reducing agent to produce a reduced polymer comprising repeating units of structure;

solution casting a film from the reduced polymer;

reacting the cast film with a fluorinating agent to produce a fluorinated film; and

contacting the fluorinated film with a sulfonating agent to prepare the polyelectrolyte film,

wherein Ar1 and Ar2 are independently selected from the group consisting of aryl ring, aryl ring system, and thiophene ring, and are optionally substituted with C 1 to C 4 alkyl groups.

10. A method according to claim 9 , wherein the sulfonating agent comprises chlorosulfonic acid.

11. A method according to claim 9 , wherein the fluorinating agent comprises DAST.

12. A method according to claim 9 , wherein Ar1 and Ar2 comprise phenyl rings.

13. A method according to claim 9 , wherein the reducing agent comprises BH 3 , the fluorinating agent comprises DAST, and the sulfonating agent comprises chlorosulfonic acid.

14. A method according to claim 9 , wherein the arylene polymer comprises repeating units of

15. A method according to claim 9 , wherein the arylene polymer comprises repeating units of

16. A fuel cell comprising

an anode,

a cathode,

a polyelectrolyte membrane disposed between the anode and cathode,

an inlet for hydrogen fuel adjacent the anode, and

an inlet for oxygen adjacent the cathode,

wherein the polyelectrolyte membrane comprises a sulfonated polymer comprising repeating units of

wherein Ar3 and Ar4 are independently selected from the group consisting of aryl ring, aryl ring system, and thiophene ring, wherein at least one of Ar3 and Ar4 is substituted with SO 3 H.

17. A fuel cell according to claim 16 , wherein the polyelectrolyte membrane has a conductivity S of 0.2 S/cm or greater at 100° C.

18. A fuel cell according to claim 16 , wherein Ar3 and Ar4 comprise phenyl rings.

19. A fuel cell according to claim 16 , wherein Ar3 comprises a thiophene ring.

20. A fuel cell according to claim 16 , wherein the ion exchange capacity is from 0.5 to 5.0 meq/g.

21. A film suitable for use as a polyelectrolyte membrane comprising a sulfonated polymer, wherein the sulfonated polymer comprises repeating units of structure

wherein Ar3 and Ar4 are independently selected from the group consisting of aryl ring, aryl ring system, and thiophene ring, wherein at least one of Ar3 and Ar4 is substituted with SO 3 H.

22. A film according to claim 21 , wherein Ar3 and Ar4 comprise phenyl rings.

23. A film according to claim 21 , wherein Ar3 comprises a thiophene ring.

Assignments (13)