Nanowire-Based Membrane Electrode Assemblies for Fuel Cells

• US 20110229795A1
• Filed: 05/31/2011
• Published: 09/22/2011
• Est. Priority Date: 12/09/2004
• Status: Active Grant

• Current Assignee: ONED Material Incorporated
• Original Assignee: Nanosys Incorporated (Shoei Electronic Materials, Inc.)
• Inventors: Chow, Calvin Y.H., Niu, Chunming, Parce, J. Wallace, Empedocles, Stephen A.
• Granted Patent: US 8,357,475 B2
• Time in Patent Office: Days
• US Class Current: 429/483
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/8846 Impregnation
• CPC Class Codes: H01M 4/8853 Electrodeposition
• CPC Class Codes: H01M 4/8867 Vapour deposition
• CPC Class Codes: H01M 4/90 Selection of catalytic material
• CPC Class Codes: H01M 4/9075 Catalytic material supported on carriers, e.g. powder carriers H01M4/8807, H01M4/881, H01M4/8814, H01M4/925 take precedence
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 4/925 supported on carriers, e.g. powder carriers
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: H01M 8/023 Porous and characterised by the material
• CPC Class Codes: H01M 8/0232 Metals or alloys
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0236 Glass; Ceramics; Cermets
• CPC Class Codes: H01M 8/0241 Composites
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• CPC Class Codes: H01M 8/1086 After-treatment of the membrane other than by polymerisation
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 977/762 : Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/948 : Energy storage/generating using nanostructure, e.g. fuel cell, battery

Abstract

The present invention discloses nanowires for use in a fuel cell comprising a metal catalyst deposited on a surface of the nanowires. A membrane electrode assembly for a fuel cell is disclosed which generally comprises a proton exchange membrane, an anode electrode, and a cathode electrode, wherein at least one or more of the anode electrode and cathode electrode comprise an interconnected network of the catalyst supported nanowires. Methods are also disclosed for preparing a membrane electrode assembly and fuel cell based upon an interconnected network of nanowires.

Claims

1. A composite comprising:

a plurality of nanowires; and

a polymer electrolyte.

2. The composite of claim 1, wherein the nanowires are dispersed within the polymer electrolyte.

3. The composite of claim 1, wherein a portion of the polymer electrolyte is attached to the nanowires.

4. The composite of claim 1, wherein a portion of the polymer electrolyte is directly linked to the surface of the nanowires.

5. The composite of claim 1, wherein a portion of the polymer electrolyte forms a continuous or discontinuous polymer film coating on the surface of the nanowires.

6. The composite of claim 1, wherein a portion of the polymer electrolyte is uniformly wetted on the surface of the nanowires.

7. The composite of claim 1, wherein the nanowires comprise an interconnected network of nanowires.

8. The composite of claim 7, wherein the nanowires comprise at least one surface chemical group which forms chemical cross-links between the interconnected nanowires.

9. The composite of claim 1, wherein the polymer electrolyte comprises an ionomer, a polyethylene oxide, a poly(ethylene succinate), a poly(beta-propiolactone), or a sulfonated fluoropolymer.

10. The composite of claim 1, wherein the polymer electrolyte is ion-conductive.

11. The composite of claim 1, wherein the surfaces of the nanowires are functionalized.

12. The composite of claim 11, wherein the nanowires are functionalized with at least one functional group which promotes wetting of the polymer electrolyte on the nanowires.

13. The composite of claim 11, wherein the nanowires are functionalized with at least one functional group which binds the polymer electrolyte to the nanowires.

14. The composite of claim 11, wherein the nanowires are functionalized with at least one molecule selected from the group consisting of:

a short chain polymer, a sulfonated hydrocarbon, a short chain sulfonated hydrocarbon, a fluorocarbon, a short chain fluorocarbon, and a branched hydrocarbon.

15. The composite of claim 11, wherein the nanowires are functionalized with at least one functional group selected from the group consisting of:

a nitric acid group, a carboxylic acid group, a hydroxyl group, an amine group, a sulfonic acid group, or a silane group.

16. The composite of claim 1, wherein the composite is porous, wherein the porous composite comprises pores disposed between the nanowires of the plurality of nanowires.

17. The composite of claim 16, wherein the polymer electrolyte is disposed within the pores of the porous composite.

18. The composite of claim 1, wherein the nanowires comprise silicon or silicon carbide.

19. The composite of claim 1, wherein the nanowires comprise crystalline silicon, polycrystalline silicon, amorphous silicon, or a mixture thereof

20. The composite of claim 1, wherein the nanowires comprise a core and one or more shell layers disposed on the core.

21. The composite of claim 1, further comprising one or more metal catalyst particles attached to the nanowires, wherein the metal catalyst particles comprise gold, copper, or mixtures or alloys thereof.

22. The composite of claim 1, wherein the nanowires are disposed on a carbon support structure.

23. The composite of claim 1, wherein the composite is electrically conductive.

24. The composite of claim 1, wherein the composite is ion-conductive.

25. An electrode comprising the composite of claim 1.

26. The electrode of claim 25, wherein the electrode comprises a conductive sheet, wherein the composite is disposed on and electrically connected to the conductive sheet.

27. The electrode of claim 25, wherein the conductive sheet comprises a metallic grid or a metallic mesh.

28. The electrode of claim 25, wherein the conductive sheet comprises graphite, carbon, or a carbon composite.

29. An anode comprising the composite of claim 1.