Polymer membrane for a fuel cell, a method of preparing the same, and a membrane-electrode assembly fuel cell system comprising the same

• US 20070015023A1
• Filed: 06/23/2006
• Published: 01/18/2007
• Est. Priority Date: 06/24/2005
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Song, Min-Kyu, Park, Young-Mi, Yoon, Hae-Kwon
• Granted Patent: US 7,588,850 B2
• Time in Patent Office: Days
• US Class Current: 429/494
• CPC Class Codes: C08J 5/22 Films, membranes or diaphragms
• CPC Class Codes: C08J 5/2275 Heterogeneous membranes
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 8/1025 having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
• CPC Class Codes: H01M 8/1027 having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/103 having nitrogen, e.g. sulfonated polybenzimidazoles [S-PBI], polybenzimidazoles with phosphoric acid, sulfonated polyamides [S-PA] or sulfonated polyphosphazenes [S-PPh]
• CPC Class Codes: H01M 8/1032 having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
• CPC Class Codes: H01M 8/1048 Ion-conducting additives, e.g. ion-conducting particles, heteropolyacids, metal phosphate or polybenzimidazole with phosphoric acid
• 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 polymer electrolyte membrane for a fuel cell, a method of preparing the same, and a fuel cell system comprising the same. The polymer electrolyte membrane includes a metal-bound inorganic ion-conductive salt and an ion-conductive cation exchange resin.

Claims

1. A polymer electrolyte membrane for a fuel cell, comprising:

a metal-bound inorganic ion-conductive salt; and

an ion-conductive cation exchange resin.

2. The polymer electrolyte membrane of claim 1, wherein the metal-bound inorganic ion-conductive salt is at least one inorganic ion-conductive salt selected from the group consisting of phosphotungstic acid, silicotungstic acid, zirconium hydrogen phosphate, α

-Zr(O_a1PCH_a2OH)_a(O_b1PC_b2H_b4SO_b5H)_b.nH₂O, wherein a1, a2, a, b1, b2, b4, b5, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, v-Zr(PO_a1)(H_a2PO_a3)_a(HO_b1PC_b2H_b3SO_b4H)_b.nH₂O, wherein a1, a2, a3, a, b1, b2, b3, b4, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, Zr(O_a1PC_a2H_a3)_aY_b, wherein a1, a2, a3, a, and b are the same or different from each other and are integers of 0 to 14, Zr(O_a1PCH_a2OH)_aY_b.nH₂O, wherein a1, a2, a, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, α

-Zr(O_a1PC_a2H_a3SO_a4H)_a.nH₂O, wherein a1, a2, a3, a4, and a are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50 and α

-Zr(O_a1POH).H₂O, wherein a1 is an integer of 0 to 14, and combinations thereof.

3. The polymer electrolyte membrane of claim 2, wherein the metal-bound inorganic ion-conductive salt is a salt of Cs-bound phosphotungstic acid.

4. The polymer electrolyte membrane of claim 1, wherein the metal is a univalent metal.

5. The polymer electrolyte membrane of claim 4, wherein the metal is selected from the group consisting of Cs, Na, K, and combinations thereof.

6. The polymer electrolyte membrane of claim 1, wherein the ion-conductive cation exchange resin is a polymer resin having a cation exchange group selected from the groups consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, derivatives thereof, and combinations thereof.

7. The polymer electrolyte membrane of claim 1, wherein the ion-conductive cation exchange resin has an ion-exchange ratio in the range of 3 to 33 and an equivalent weight in the range of 700 to 2000.

8. The polymer electrolyte membrane of claim 1, wherein the ion-conductive cation exchange resin is selected from the group consisting of perfluoro-based polymers, benzimidazole-based polymers, polyimide-based polymers, polyetherimide-based polymers, polyphenylenesulfide-based polymers, polysulfone-based polymers, polyethersulfone-based polymers, polyetherketone-based polymers, polyether-etherketone-based polymers, polyphenylquinoxaline-based polymers, and combinations thereof.

9. The polymer electrolyte membrane of claim 1, wherein an inorganic ion-conductive salt bound with the metal is in the range of from 1 to 20 parts by weight based on 100 parts by weight of the ion-conductive cation exchange resin.

10. The polymer electrolyte membrane of claim 1, further comprising an inorganic additive.

11. The polymer electrolyte membrane of claim 10, wherein the inorganic additive is selected from the group consisting of silica, clay, alumina, mica, zeolite, and combinations thereof.

12. The polymer electrolyte membrane of claim 10, wherein the inorganic additive is included in an amount in the range of 1 to 10 parts by weight based on 100 parts by weight of the entire polymer electrolyte membrane.

13. A method of preparing the polymer electrolyte membrane for a fuel cell, comprising:

preparing a salt of a metal-bound inorganic ion conductor by reacting a metal compound and an inorganic ion conductor in a solvent;

mixing the inorganic ion-conductive salt with an ion-conductive cation polymer resin solution; and

casting or electrospinning the mixture.

14. The method of claim 13, wherein the inorganic ion conductor is at least one selected from the group consisting of phosphotungstic acid, silicotungstic acid, zirconium hydrogen phosphate, α

-Zr(O_a1PCH_a2OH)_a(O_b1PC_b2H_b4SO_b5H)_b.nH₂O, wherein a1, a2, a, b1, b2, b4, b5, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to

     50), v-Zr(PO_a1) (H_a2PO_a3)_a(HO_b1PC_b2H_b3SO_b4H)_b.nH₂O, wherein a1, a2, a3, a, b1, b2, b3, b4, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, Zr(O_a1PC_a2H_a3)_aY_b, wherein a1, a2, a3, a, and b are the same or different from each other and are integers of 0 to 14, Zr(O_a1PCH_a2OH)_aY_b.nH₂O, wherein a1, a2, a, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, α

-Zr(O_a1PC_a2H_a3SO_a4H)_a.nH₂O, wherein a1, a2, a3, a4, and a are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50 and α

-Zr(O_a1POH).H₂O, wherein a1 is an integer of 0 to 14, and combinations thereof.

15. The method of claim 13, wherein the metal compound includes a metal selected from the group consisting of Cs, Na, K, and combinations thereof.

16. The method of claim 13, wherein the solvent is selected from the group consisting of water;

an alcohol selected from the group consisting of methanol, ethanol, and propanol;

N-methyl-2-pyrrolidinone;

dimethyl formamide;

dimethyl acetamide;

tetrahydrofuran;

dimethyl sulfoxide;

acetone;

methyl ethyl ketone;

tetramethyl urea;

trimethyl phosphate;

butyrolactone;

isophorone;

carbitol acetate;

methylisobutylketone;

N-butyl acetate;

cyclohexanone;

diacetone alcohol;

diisobutyl ketone;

ethylacetoacetate;

glycol ether;

propylene carbonate;

ethylene carbonate;

dimethyl carbonate;

diethyl carbonate; and

mixtures thereof.

17. The method of claim 13, further comprising firing the resulting product after reacting the metal compound and inorganic ion conductor in the solvent.

18. The method of claim 17, wherein the firing is performed in the range of 300 to 350°

C.

19. The method of claim 13, wherein the inorganic ion-conductive salt is mixed in a weight ratio in the range of 1 to 20 parts by weight with the ion-conductive cation polymer resin solution based on 100 parts by weight of the ion-conductive cation polymer resin.

20. The method of claim 13, wherein the ion-conductive cation polymer resin solution is in a concentration in the range of 0.5 to 30 wt %.

21. The method of claim 13, further comprising adding an inorganic additive to the mixture.

22. The method of claim 21, wherein the inorganic additive is selected from the group consisting of silica, clay, alumina, mica, zeolite, and combinations thereof.

23. The method of claim 21, wherein the inorganic additive is added in an amount in the range of 1 to 20 parts by weight based on 100 parts by weight of the total mixture.

24. A fuel cell system comprising at least one electricity generating element comprising:

at least one membrane-electrode assembly comprising an anode and a cathode positioned on opposite sides of a polymer electrolyte membrane that is interposed therebetween, wherein the polymer electrolyte membrane comprises a metal-bound inorganic ion-conductive salt and an ion-conductive cation exchange resin;

separators on opposite sides of the polymer electrolyte membrane for generating electricity through an oxidation reaction of a fuel and a reduction reaction of an oxidant;

a fuel supplier for supplying the fuel to the electricity generating element; and

an oxidant supplier for supplying the oxidant to the electricity generating element.

25. The fuel cell system of claim 24, wherein the metal-bound inorganic ion-conductive salt is at least one selected from the group consisting of phosphotungstic acid, silicotungstic acid, zirconium hydrogen phosphate, α

-Zr(O_a1PCH_a2OH)_a(O_b1PC_b2H_b4SO_b5H)_b.nH₂O, wherein a1, a2, a, b1, b2, b4, b5, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, v-Zr(PO_a1)(H_a2PO_a3)_a(HO_b1PC_b2H_b3SO_b4H)_b.nH₂O, wherein a1, a2, a3, a, b1, b2, b3, b4, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, Zr(O_a1PC_a2H_a3)_aY_b, wherein a1, a2, a3, a, and b are the same or different from each other and are integers of 0 to 14, Zr(O_a1PCH_a2OH)_aY_b.nH₂O, wherein a1, a2, a, and b are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50, α

-Zr(O_a1PC_a2H_a3SO_a4H)_a.nH₂O, wherein a1, a2, a3, a4, and a are the same or different from each other and are integers of 0 to 14, and n is an integer of 0 to 50 and α

-Zr(O_a1POH).H₂O, wherein a1 is an integer of 0 to 14, and combinations thereof.

26. The fuel cell system of claim 25, wherein the metal-bound inorganic ion-conductive salt is a Cs-bound phosphotungstic acid salt.

27. The fuel cell system of claim 24, wherein the metal is a univalentmetal.

28. The fuel cell system of claim 27, wherein the metal is selected from the group consisting of Cs, Na, K, and combinations thereof.

29. The fuel cell system of claim 24, wherein the ion-conductive cation exchange resin has a cation exchange group selected from the groups consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, derivatives thereof, and combinations thereof.

30. The fuel cell system of claim 24, wherein the ion-conductive cation exchange resin has an ion-exchange ratio in the range of 3 to 33 and an equivalent weight in the range of 700 to 2000.

31. The fuel cell system of claim 24, wherein the ion-conductive cation exchange resin is selected from the group consisting of perfluoro-based polymers, benzimidazole-based polymers, polyimide-based polymers, polyetherimide-based polymers, polyphenylenesulfide-based polymers, polysulfone-based polymers, polyethersulfone-based polymers, polyetherketone-based polymers, polyether-etherketone-based polymers, polyphenylquinoxaline-based polymers, and combinations thereof.

32. The fuel cell system of claim 24, wherein an inorganic ion-conductive salt bound with the metal has a ratio in the range of 1 to 20 parts by weight based on 100 parts by weight of the ion-conductive cation exchange resin.

33. The fuel cell system of claim 24, wherein the polymer electrolyte membrane further comprises an inorganic additive.

34. The fuel cell system of claim 33, wherein the inorganic additive is selected from the group consisting of silica, clay, alumina, mica, zeolite, and combinations thereof.

35. The fuel cell system of claim 33, wherein the inorganic additive is added in a ratio in the range of 1 to 10 parts by weight based on 100 parts by weight of the entire amount of the polymer electrolyte membrane.