Membrane-electrode assembly for solid polymer electrolyte fuel cells and process for its production

• US 20030008198A1
• Filed: 05/31/2002
• Published: 01/09/2003
• Est. Priority Date: 05/31/2001
• Status: Abandoned Application

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Kinoshita, Shinji, Mukoyama, Atsushi, Ishisaki, Azusa, Ishisaki, Toyoaki
• Application Number:
  US10/158,145
• Publication Number:
  US 20030008198A1
• Time in Patent Office: Days
• US Class Current: 429/42
• CPC Class Codes: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 5/2275 Heterogeneous membranes
• CPC Class Codes: C08J 5/2281 fluorine containing heterogeneous membranes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0091 in the form of mixtures
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8652 as mixture
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1081 starting from solutions, dispersions or slurries exclusively of polymers
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells, which comprises bonding electrodes having a catalyst layer containing a catalyst as a cathode and an anode onto both sides of a cation exchange membrane as a solid polymer electrolyte membrane, wherein the cation exchange membrane is formed from a dispersion having a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer dispersed in a dispersion medium.

Claims

1. A process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells, which comprises bonding electrodes having a catalyst layer containing a catalyst as a cathode and an anode onto both sides of a cation exchange membrane as a solid polymer electrolyte membrane, wherein the cation exchange membrane is formed from a dispersion having a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer dispersed in a dispersion medium.

4. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 1, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion.

5. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 1, wherein the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

6. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 1, wherein the fluorinated polymer having sulfonic acid groups is a copolymer comprising polymerization units derived from tetrafluoroethylene and polymerization units derived from CF₂=CF(OCF₂CFX)_m-O_p-(CF₂)_nSO₃H (wherein X is a fluorine atom or a trifluoromethyl group, A is a sulfonic acid group or its precursor, m is an integer of from 0 to 3, n is an integer of from 0 to 12, and p is 0 or 1, provided that when n is 0, p is also 0).

2. A process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells, which comprises bonding electrodes having a catalyst layer containing a catalyst as a cathode and an anode onto both sides of a cation exchange membrane as a solid polymer electrolyte membrane, wherein the catalyst layer of the cathode and/or the anode is formed from a mixture of a dispersion having a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer dispersed in a dispersion medium, and a catalyst.

3. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the cation exchange membrane is formed from a dispersion having a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer dispersed in a dispersion medium.

7. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion, and the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

8. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion.

9. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

10. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the fluorinated polymer having sulfonic acid groups is a copolymer comprising polymerization units derived from tetrafluoroethylene and polymerization units derived from CF₂=CF(OCF₂CFX)_m-O_p-(CF₂)_nSO₃H (wherein X is a fluorine atom or a trifluoromethyl group, A is a sulfonic acid group or its precursor, m is an integer of from 0 to 3, n is an integer of from 0 to 12, and p is 0 or 1, provided that when n is 0, p is also 0).

11. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 3, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion, and the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

12. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 3, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion.

13. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 3, wherein the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

14. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 3, wherein the fluorinated polymer having sulfonic acid groups is a copolymer comprising polymerization units derived from tetrafluoroethylene and polymerization units derived from CF₂=CF(OCF₂CFX)_m-O_p-(CF₂)_nSO₃H (wherein X is a fluorine atom or a trifluoromethyl group, A is a sulfonic acid group or its precursor, m is an integer of from 0 to 3, n is an integer of from 0 to 12, and p is 0 or 1, provided that when n is 0, p is also 0).

15. The process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 2, wherein the dispersion contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the solid mass of the dispersion, and the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

17. The membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 16, wherein the catalyst layer of the cathode and/or the catalyst layer of the anode contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the total amount of the fibrilliform fluorocarbon polymer and the fluorinated polymer having sulfonic acid groups.

18. The membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 16, wherein the cation exchange membrane comprises a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer.

19. The membrane-electrode assembly for solid polymer electrolyte fuel cells according to claim 16, wherein the fibrilliform fluorocarbon polymer is a polytetrafluoroethylene or a copolymer comprising at least 95 mol % of polymerization units derived from tetrafluoroethylene.

16. A membrane-electrode assembly for solid polymer electrolyte fuel cells which comprises a cation exchange membrane as a solid polymer electrolyte membrane and electrodes having a catalyst layer containing a catalyst as a cathode and an anode bonded onto both sides of the cation exchange membrane, wherein the catalyst layer of the cathode and/or the catalyst layer of the anode comprises a fluorinated polymer having sulfonic acid groups as an ion exchange polymer, a fibrilliform fluorocarbon polymer and a catalyst.

20. A solid polymer electrolyte fuel cell which comprises a membrane-electrode assembly for solid polymer electrolyte fuel cells comprising a cation exchange membrane as a solid polymer electrolyte membrane, electrodes having a catalyst layer containing a catalyst as a cathode and an anode bonded onto both sides of the cation exchange membrane, wherein the catalyst layer of the cathode and/or the catalyst layer of the anode comprises a fluorinated polymer having sulfonic acid groups as an ion exchange polymer, a fibrilliform fluorocarbon polymer and a catalyst, and an oxygen-containing gas and a hydrogen-containing gas are fed to the cathode and the anode, respectively.

21. The solid polymer electrolyte fuel cell according to claim 20, wherein the cation exchange membrane comprises a fluorinated polymer having sulfonic acid groups as an ion exchange polymer and a fibrilliform fluorocarbon polymer.

22. The solid polymer electrolyte fuel cell according to claim 20, wherein the catalyst layer of the cathode and/or the catalyst layer of the anode contains the fibrilliform fluorocarbon polymer in an amount of from 0.5 to 15 mass % of the total amount of the fibrilliform fluorocarbon polymer and the fluorinated polymer having sulfonic acid groups.