Polymer electrolyte membrane, membrane electrode assembly, and solid polymer electrolyte fuel cell

Patent metadata

Field	Value
Publication number	US-11211626-B2
Application number	US-201716611584-A
Country	US
Kind code	B2
Filing date	May 11, 2017
Priority date	May 11, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A polymer electrolyte membrane of the present disclosure comprises a perfluorosulfonic acid resin (A), wherein the polymer electrolyte membrane has a phase-separation structure having a phase where fluorine atoms are detected in majority and a phase where carbon atoms are detected in majority, in an image of a membrane surface observed under an SEM-EDX, and the polymer electrolyte membrane has a phase having an average aspect ratio of 1.5 or more and 10 or less in an image of a membrane cross-section observed under an SEM.

First claim

The invention claimed is:

1. A polymer electrolyte membrane comprising:
a perfluorosulfonic acid resin (A),
wherein the polymer electrolyte membrane has a phase-separation structure having a phase where fluorine atoms are detected in majority and a phase where carbon atoms are detected in majority, in an image of a membrane surface observed under an SEM-EDX, and
the polymer electrolyte membrane has a phase having an average aspect ratio of 1.5 or more and 10 or less in an image of a membrane cross-section observed under an SEM.

2. The polymer electrolyte membrane of claim 1 , wherein a proportion of a relative standard deviation of a carbon-fluorine peak intensity ratio at a magnification of ×1,500 and a relative standard deviation of a carbon-fluorine peak intensity ratio at a magnification of ×150 (the relative standard deviation at ×1,500/the relative standard deviation at ×150) in the image of the membrane surface observed under the SEM-EDX is 0.20 or more and 5.0 or less.

3. The polymer electrolyte membrane of claim 2 , wherein
an average carbon-fluorine peak intensity ratio at a magnification of ×1,500 in the image of the membrane surface observed under the SEM-EDX is 0.50 or more and 20 or less, and
a hydrogen permeability coefficient at 80° C. and in a relative humidity (RH) of 30% is 5.0×10 −9 cc·cm/cm 2 ·s·cmHg or less.

4. The polymer electrolyte membrane of claim 1 , wherein the phase-separation structure is a sea-island structure.

5. The polymer electrolyte membrane of claim 1 , further comprising an acidic group-containing aromatic hydrocarbon resin (B).

6. The polymer electrolyte membrane of claim 5 , wherein a mass ratio of the perfluorosulfonic acid resin (A) and the acidic group-containing aromatic hydrocarbon resin (B) (a mass of the resin (A)/a mass of the resin (B)) is 90/10 to 50/50.

7. The polymer electrolyte membrane of claim 5 , further comprising a compatibilizer (C) for the perfluorosulfonic acid resin (A) and the acidic group-containing aromatic hydrocarbon resin (B).

8. The polymer electrolyte membrane of claim 5 , wherein the polymer electrolyte membrane is produced through a step of mixing a solution containing the perfluorosulfonic acid resin (A) and a solution containing the acidic group-containing aromatic hydrocarbon resin (B).

9. The polymer electrolyte membrane of claim 8 , wherein peak tops of scattering diameters of the solution containing the perfluorosulfonic acid resin (A) and the solution containing the acidic group-containing aromatic hydrocarbon resin (B) in a dynamic light scattering measurement are within a range of 10 μm or more and 200 μm or less.

10. The polymer electrolyte membrane of claim 7 , wherein the polymer electrolyte membrane is produced through a step of mixing the solution containing the perfluorosulfonic acid resin (A), the solution containing the acidic group-containing aromatic hydrocarbon resin (B), and a solution containing the compatibilizer (C).

11. The polymer electrolyte membrane of claim 10 , wherein a mixed solution of the solution containing the perfluorosulfonic acid resin (A), the solution containing the acidic group-containing aromatic hydrocarbon resin (B), and the solution containing the compatibilizer (C) has a transmittance of 90% T or more at a wavelength of 800 nm in an UV measurement.

12. The polymer electrolyte membrane of claim 10 , wherein a solid content concentration of the compatibilizer (C) in the mixed solution of the solution containing the perfluorosulfonic acid resin (A), the solution containing the acidic group-containing aromatic hydrocarbon resin (B), and the solution containing the compatibilizer (C) is 0.001% by mass or more and less than 1% by mass.

13. The polymer electrolyte membrane of claim 1 , comprising:
a layer containing the perfluorosulfonic acid resin (A) and the acidic group-containing aromatic hydrocarbon resin (B); and
a layer containing the perfluorosulfonic acid resin (A).

14. A membrane electrode assembly comprising the polymer electrolyte membrane of claim 1 and an electrode catalyst layer.

15. A solid polymer electrolyte fuel cell comprising the membrane electrode assembly of claim 14 .

16. The polymer electrolyte membrane of claim 2 , wherein the phase-separation structure is a sea-island structure.

17. The polymer electrolyte membrane of claim 2 , further comprising an acidic group-containing aromatic hydrocarbon resin (B).

18. The polymer electrolyte membrane of claim 2 , comprising:
a layer containing the perfluorosulfonic acid resin (A) and the acidic group-containing aromatic hydrocarbon resin (B); and
a layer containing the perfluorosulfonic acid resin (A).

19. A membrane electrode assembly comprising the polymer electrolyte membrane of claim 2 and an electrode catalyst layer.

Assignees

• Asahi Chemical Ind

Inventors

• Tago Takahiro
• Miyazaki Kuon

Classifications

• C08L71/12

  Polyphenylene oxides · CPC title

• C25B13/08

  based on organic materials · CPC title

• C08J5/22

  Films, membranes or diaphragms · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• C08G65/485 Primary

  Polyphenylene oxides · CPC title