Solid polymer electrolyte and process for making same

Patent metadata

Field	Value
Publication number	US-9847533-B2
Application number	US-63383509-A
Country	US
Kind code	B2
Filing date	Dec 9, 2009
Priority date	Sep 26, 2005
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A solid polymer electrolyte membrane having a first surface and a second surface opposite the first surface, where the solid polymer electrolyte membrane has a failure force greater than about 115 grams and comprises a composite membrane consisting essentially of (a) at least one expanded PTFE membrane having a porous microstructure of polymeric fibrils, and (b) at least one ion exchange material impregnated throughout the porous microstructure of the expanded PTFE membrane so as to render an interior volume of the expanded PTFE membrane substantially occlusive; (c) at least one substantially occlusive, electronically insulating first composite layer interposed between the expanded PTFE membrane and the first surface, the first composite layer comprising a plurality of first carbon particles supporting a catalyst comprising platinum and an ion exchange material, wherein a plurality of the first carbon particles has a particle size less than about 75 nm, or less than about 50 nm, or less than about 25 nm.

First claim

We claim:

1. A method of making a solid polymer electrolyte membrane for use interposed between a separate anode and cathode comprising the steps of
(a) preparing an ink solution comprising a precious metal catalyst on a supporting particle and an ion exchange material,
wherein preparing said ink solution comprises passing said ink solution through a high shear mixer;
(b) providing a polymeric support having a first surface, a second surface opposite said first surface, and a microstructure of micropores;
(c) applying a solution comprising an ion exchange resin to said first surface, thereby impregnating said microstructure with said ion exchange resin to form a substantially air occlusive, electronically insulating first composite layer, and
(d) applying said ink solution to at least one of said first and second surfaces, thereby impregnating said microstructure with said ink solution to form a substantially air occlusive, electronically insulating second composite layer,
thereby forming said solid polymer electrolyte membrane.

2. The method of claim 1 wherein the concentration of said precious metal catalyst based on weight percent of dry ion exchange material is between about 0.1% and 10%.

3. The method of claim 2 wherein the concentration of said precious metal catalyst based on weight percent of dry ion exchange material is between about 0.5% and 3%.

4. The method of claim 3 wherein the concentration of said precious metal catalyst based on weight percent of dry ion exchange material is about 1%.

5. The method of claim 3 wherein the concentration of said precious metal catalyst based on weight percent of dry ion exchange material is about 2.5%.

6. The method of claim 1 wherein step (a) further includes (a1) reducing the concentration of large particles in the ink.

7. The method of claim 6 wherein the step of reducing the concentration of large particles in the ink comprises filtering.

8. The method of claim 6 wherein the step of reducing the concentration of large particles in the ink comprises the use of a centrifuge.

9. The method of claim 1 wherein said high shear mixer is a microfluidizer.

10. The method of claim 1 wherein said high shear mixer is a rotor-stator mixer comprising at least one stage.

11. The method of claim 1 wherein said step (d) further includes (d1) applying said ink solution to a thin polymer film and (d2) applying at least one of said first and second surfaces to said ink solution on said thin polymer film.

12. The method of claim 11 wherein said thin polymer film comprises polyethylene, polyethylene terephthalate polypropylene, poly vinylidene chloride, polytetrafluoroethylene, polyesters, or combinations thereof.

13. The method of claim 12 wherein said thin polymer film further comprises a coating capable of enhancing the release characteristics of said polymer film.

14. The method of claim 11 wherein said step (c) further includes (c1) drying said support after impregnation of said ion exchange resin.

15. The method of claim 9 wherein said high shear mixer is a microfluidizer operating at a pressure between about 1,000 and about 25,000 psi.

16. The method of claim 14 wherein step (d) further includes (d1) drying said support after application of said ink solution.

17. The method of claim 14 wherein there is a further step after step (d) of heating said solid polymer electrolyte membrane at an elevated temperature.

18. The method of claim 17 wherein said elevated temperature is between about 100 degrees C. and about 175 degrees C.

19. The method of claim 18 wherein said elevated temperature is between about 120 degrees C. and about 160 degrees C.

20. The method of claim 19 wherein said solid polymer electrolyte membrane is held at said elevated temperature for between about 1 minute and about 10 minutes.

21. The method of claim 20 wherein said solid polymer electrolyte membrane is held at said elevated temperature for between about 3 minutes and about 5 minutes.

22. The method of claim 2 wherein said supporting particle comprises carbon.

23. The method of claim 22 wherein said precious metal catalyst comprises platinum.

24. The method of claim 23 , wherein said polymer support comprises expanded polytetrafluoroethylene.

25. The method of claim 1 , wherein:
the supporting particle in step (a) is a carbon particle;
and the polymeric support in step (b) is an expanded polytetrafluoroethylene membrane;
and wherein the method further comprises the steps of
(c1) drying said expanded polytetrafluoroethylene membrane after impregnation of said ion exchange resin;
(d1) applying said ink solution to a thin polymer film;
(d2) applying said second surface of said expanded polytetrafluoroethylene membrane to said ink solution on said thin polymer film;
(d3) drying said expanded polytetrafluoroethylene membrane after impregnation of said ink solution and removing said thin polymer film.

Assignees

• Berta Thomas
• Shamrock William
• Gore & Ass

Inventors

• Berta Thomas
• Shamrock William

Classifications

• H01M8/1025

  having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters · CPC title

• H01M4/881

  Electrolytic membranes · CPC title

• Y02E60/521

  Cross-Sectional Technologies · mapped topic

• H01M4/8807 Primary

  Gas diffusion layers · CPC title

• H01M8/106

  characterised by the chemical composition of the porous support · CPC title