PROTON-CONDUCTIVE POLYMER ELECTROLYTE MEMBRANE, METHOD OF MANUFACTURING THE PROTON-CONDUCTIVE POLYMER ELECTROLYTE MEMBRANE, AND MEMBRANE-ELECTRODE ASSEMBLY AND POLYMER ELECTROLYTE FUEL CELL USING THE PROTON-CONDUCTIVE POLYMER ELECTROLYTE MEMBRANE

• US 20110027692A1
• Filed: 03/03/2009
• Published: 02/03/2011
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Toshikawa, Sakura, Sugitani, Tooru, Nishii, Hiroyuki, Yamada, Otoo
• Granted Patent: US 8,304,135 B2
• Time in Patent Office: Days
• US Class Current: 429/493
• CPC Class Codes: C08J 2329/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C08J 5/2275 Heterogeneous membranes
• CPC Class Codes: C08J 5/2287 After-treatment
• CPC Class Codes: H01B 1/122 Ionic conductors
• CPC Class Codes: H01M 8/04253 Means for solving freezing problems
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• 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 8/1069 characterised by the manufacturing processes
• 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 method of manufacturing a proton-conductive polymer electrolyte membrane using polyvinyl alcohol (PVA) as a base material and having excellent proton conductivity and methanol blocking properties is provided. The method includes: heat-treating a precursor membrane including PVA and a water-soluble polymer electrolyte having a proton conductive group to proceed crystallization of the PVA; and chemically crosslinking the heat-treated precursor membrane with a crosslinking agent reactive with the PVA, to form a polymer electrolyte membrane in which a crosslinked PVA is a base material and protons are conducted through the electrolyte retained in the base material. The content of a water-soluble polymer except the PVA and the water-soluble polymer electrolyte in the precursor membrane is in a weight ratio of less than 0.1 with respect to the PVA.

Claims

1. A method of manufacturing a proton-conductive polymer electrolyte membrane, comprising:

heat-treating a precursor membrane comprising polyvinyl alcohol (PVA) and a water-soluble polymer electrolyte having a proton conductive group to proceed crystallization of the PVA; and

chemically crosslinking the heat-treated precursor membrane with a crosslinking agent reactive with the PVA, to form a polymer electrolyte membrane in which a crosslinked PVA is a base material and protons are conducted through the electrolyte retained in the base material,

wherein the content of a water-soluble polymer except the PVA and the water-soluble polymer electrolyte in the precursor membrane is in a weight ratio of less than 0.1 with respect to the PVA.

2. The method of manufacturing a proton-conductive polymer electrolyte membrane according to claim 1, wherein the proton conductive group is a sulfonic acid group or a phosphoric acid group.

3. The method of manufacturing a proton-conductive polymer electrolyte membrane according to claim 1, wherein the water-soluble polymer electrolyte is at least one selected from the group consisting of polystyrene sulfonic acid, polyvinyl sulfonic acid, poly(2-acrylamide-2-methylpropanesulfonic acid), sulfonated poly(ether ether ketone), and sulfonated poly(ether sulfone).

4. The method of manufacturing a proton-conductive polymer electrolyte membrane according to claim 1, wherein the content of the water-soluble polymer electrolyte in the precursor membrane is in a weight ratio of from 0.05 to 1 with respect to the PVA.

5. A proton-conductive polymer electrolyte membrane obtained by the method according to claim 1.

7. A membrane-electrode assembly comprising:

a polymer electrolyte membrane, and a pair of electrodes disposed so as to sandwich the electrolyte membrane, wherein

the electrolyte membrane is a proton-conductive polymer electrolyte membrane according to claim 5.

9. A polymer electrolyte fuel cell comprising:

a polymer electrolyte membrane;

a pair of electrodes disposed so as to sandwich the electrolyte membrane; and

a pair of separators disposed so as to sandwich the pair of electrodes, wherein

the electrolyte membrane is a proton-conductive polymer electrolyte membrane according to claim 5.

11. The polymer electrolyte fuel cell according to claim 9, being a direct methanol fuel cell.

6. A proton-conductive polymer electrolyte membrane comprising:

a base material comprising a crosslinked polyvinyl alcohol (PVA); and

a proton-conductive water-soluble polymer electrolyte retained in the base material, wherein

the content of a water-soluble polymer except the PVA and the water-soluble polymer electrolyte is in a weight ratio of less than 0.1 with respect to the PVA.

8. A membrane-electrode assembly comprising:

a polymer electrolyte membrane, and a pair of electrodes disposed so as to sandwich the electrolyte membrane, wherein

the electrolyte membrane is a proton-conductive polymer electrolyte membrane according to claim 6.

10. A polymer electrolyte fuel cell comprising:

a polymer electrolyte membrane;

a pair of electrodes disposed so as to sandwich the electrolyte membrane; and

a pair of separators disposed so as to sandwich the pair of electrodes, wherein

the electrolyte membrane is a proton-conductive polymer electrolyte membrane according to claim 6.

12. The polymer electrolyte fuel cell according to claim 10, being a direct methanol fuel cell.