Membrane-electrode junction agent, proton conducting membrane having junction layer, membrane-electrode assembly, polymer electrolyte fuel cell, and manufacturing method of the membrane-electrode assembly

• US 8,318,377 B2
• Filed: 03/12/2008
• Issued: 11/27/2012
• Est. Priority Date: 03/16/2007
• Status: Expired due to Fees

• Current Assignee: Sekisui Chemical Company Limited (Sekisui)
• Original Assignee: Sekisui Chemical Company Limited (Sekisui)
• Inventors: Konno, Yoshiharu, Nakajima, Hideyasu, Miyami, Toshihito, Kanoh, Masashi
• Primary Examiner(s): Kalafut, Stephen J.
• Application Number:
  US12/531,242
• Publication Number:
  US 20100047659A1
• Time in Patent Office: 1,721 Days
• Field of Search: 429/492, 429/493, 429/535, 106/287.1, 106/287.16
• US Class Current: 429/492
• CPC Class Codes: H01M 8/0258 characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
• CPC Class Codes: H01M 8/0297 Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other H01M8/0271 takes precedence
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• 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 membrane-electrode junction agent, a proton conducting membrane having a junction layer, a membrane-electrode assembly, a polymer electrolyte fuel cell, and a manufacturing method of the membrane-electrode assembly, which enhance the power generation performance, realize the high fuel barrier property, and are capable of enhancing the joint strength between the membrane and the electrodes, is provided. A membrane-electrode junction agent that joins a proton conducting membrane and electrodes arranged on both surfaces of the proton conducting membrane to each other, the membrane-electrode junction agent including: a cross-linked compound (X) having a silicon-oxygen bond; a polymer material (Y) containing an acid group; and a hydrophilic resin (Z) containing no acid group.

Claims

1. A membrane-electrode junction agent useful for joining a proton conducting membrane and electrodes arranged on both surfaces of the proton conducting membrane, comprising:

a cross-linkable compound (X) having a silicon-oxygen bond;

a polymer material (Y) containing an acid group, and

a hydrophilic resin (Z) containing no acid group.

2. The membrane-electrode junction agent according to claim 1, wherein the polymer material (Y) is a composite of a monomer (V) containing an acid group and a monomer (W) not containing an acid group and containing silicon.

3. The membrane-electrode junction agent according to claim 1, wherein the polymer material (Y) contains:

an acid group-containing polymer obtained by polymerizing a monomer (V′

) having an acid group; and

a polymerizable unsaturated double bond.

4. The membrane-electrode junction agent according to claim 1, wherein the acid group is any of a sulfonic acid group, a carboxylic acid group and a phosphoric acid group.

5. The membrane-electrode junction agent according to claim 1, wherein the cross linkable compound (X) contains an aqueous solution of silica and/or silicate.

6. The membrane-electrode junction agent according to claim 1, wherein the cross linkable compound (X) contains:

liquid alkoxysilane; and

an aqueous solution of silica and/or silicate.

7. The membrane-electrode junction agent according to claim 1, wherein the hydrophilic resin (Z) containing no acid group is either polyvinyl alcohol or polyethylene glycol.

8. A proton conducting membrane structure comprising:

a proton conducting membrane; and

a junction layer formed of a membrane-electrode junction agent, being provided on one surface or both surfaces of the proton conducting membrane,

wherein said membrane-electrode junction agent comprises a cross-linkable compound (X) having a silicon-oxygen bond;

a polymer material (Y) containing an acid group and a hydrophilic resin (Z) containing no acid group.

9. The proton conducting membrane structure according to claim 8, wherein the cross linkable compound (X) and the polymer material (Y) are bonded to each other by a silicon-oxygen bond.

10. The proton conducting membrane structure according to claim 8, wherein the junction layer is composed of a continuum of particles, and in addition, an acid group is imparted to surfaces of the particles, and proton conduction paths is formed in gaps among the particles.

11. The proton conducting membrane structure according to claim 10, wherein an average particle diameter of the particles is 3 to 200 nm.

12. The proton conducting membrane structure according to claim 8, wherein the proton conducting membrane has a cross-linked structure.

13. The proton conducting membrane structure according to claim 8, wherein the proton conducting membrane is a proton conducting membrane comprising:

an acid group-containing structure (H); and

a silicon-oxygen bonding structure (A) containing a cross-linked structure by a silicon-oxygen bond, and the silicon-oxygen bonding structure (A) is a structure represented by a following general formula (I);

14. The proton conducting membrane structure according to claim 8, wherein the proton conducting membrane is a proton conducting membrane comprising a silicon-oxygen bonding structure (A) containing a cross-linked structure by a silicon-oxygen bond and an acid group-containing structure (B) covalently bonded to a silane compound and having an acid group, being coupled to each other by a silicon-oxygen bond,

wherein the silicon-oxygen bonding structure (A) is a structure represented by a following general formula (I):

15. The proton conducting membrane structure according to claim 8, wherein the proton conducting membrane is a proton conducting membrane comprising a silicon-oxygen bonding structure (A) containing a cross-linked structure by a silicon-oxygen bond and an acid group-containing structure (B) covalently bonded to a silane compound and having an acid group, being coupled to each other by a silicon-oxygen bond,

wherein the silicon-oxygen bonding structure (A) is a structure represented by a following general formula (I):

16. A membrane-electrode assembly comprising:

a proton conducting membrane;

a junction layer formed of a membrane-electrode junction agent and being provided on both surfaces of the proton conducting membrane;

a fuel electrode; and

an air electrode,

wherein said membrane-electrode junction agent comprises a cross-linkable compound (X) having a silicon-oxygen bond;

a polymer material (Y) containing an acid group and a hydrophilic resin (Z) containing no acid group.

17. A polymer electrolyte fuel cell comprising the membrane-electrode assembly according to claim 16.

18. A polymer electrolyte fuel cell comprising:

a unit cell made of the membrane-electrode assembly according to claim 16; and

a pair of separators which serve as passages of fuel and air, being arranged on outsides of the unit cell,

wherein a plurality of the unit cells adjacent to one another are coupled to one another.

19. A manufacturing method of a membrane-electrode assembly, comprising:

forming a membrane having a junction layer by coating a membrane-electrode junction agent, comprising a cross-linkable compound (X) having a silicon-oxygen bond and a polymer material (Y) containing an acid group on both surfaces of a proton conducting membrane, followed by drying;

softening and/or swelling the membrane having the junction layer by impregnating a polar solvent into the membrane having the junction layer; and

pasting a fuel electrode and an air electrode to the softened and/or swelled membrane having the junction layer, followed by heat pressing.

20. A proton conducting membrane structure comprising:

a proton conducting membrane; and

a junction layer formed of a membrane-electrode junction agent, being provided on one surface or both surfaces of the proton conducting membrane,

wherein said membrane-electrode junction agent comprises a cross-linkable compound (X) having a silicon-oxygen bond and a polymer material (Y) containing an acid group,

wherein the junction layer is composed of a continuum of particles, and in addition, an acid group is imparted to surfaces of the particles, and proton conduction paths is formed in gaps among the particles.

21. The proton conducting membrane structure according to claim 20, wherein an average particle diameter of the particles is 3 to 200 nm.