Nanowire-based membrane electrode assemblies for fuel cells

• US 8,440,369 B2
• Filed: 07/17/2012
• Issued: 05/14/2013
• Est. Priority Date: 12/09/2004
• Status: Active Grant

• Current Assignee: ONED Material Incorporated
• Original Assignee: Nanosys Incorporated (Shoei Electronic Materials, Inc.)
• Inventors: Niu, Chunming, Chow, Calvin Y. H., Empedocles, Stephen A., Parce, J. Wallace
• Primary Examiner(s): Kalafut, Stephen J.
• Application Number:
  US13/551,230
• Publication Number:
  US 20120282540A1
• Time in Patent Office: 301 Days
• Field of Search: 429/492, 429/532, 429/530, 502/177, 502/232, 977/762
• US Class Current: 429/530
• 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 composition comprising:

a plurality of nanowires attached directly to a support structure comprising graphite, carbon or a carbon composition, the nanowires comprising crystalline silicon, polycrystalline silicon, amorphous silicon, or a mixture thereof; and

an electrolyte.

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

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

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

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

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

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

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

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

10. The composition of claim 1, wherein the surfaces of the nanowires are functionalized.

11. The composition of claim 10, wherein the nanowires are functionalized with at least one functional group which promotes wetting of the electrolyte on the nanowires.

12. The composition of claim 10, wherein the nanowires are functionalized with at least one functional group which binds the electrolyte to the nanowires.

13. The composition of claim 10, 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.

14. The composition of claim 10, 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.

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

16. The composition of claim 15, wherein the electrolyte is disposed within the pores of the porous composition.

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

18. The composition 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.

19. The composition of claim 1, wherein the nanowires are grown on the support structure.

20. The composition of claim 1, wherein the composition is electrically conductive.

21. An electrode comprising the composition of claim 1.

22. An anode comprising the composition of claim 1.

23. An article, comprising:

an anode;

a cathode;

an electrolyte, and

wherein the anode comprises a substrate and a plurality of nanowires attached directly to the substrate, the substrate comprises graphite, carbon or a carbon composition, and the nanowires comprise crystalline silicon, polycrystalline silicon, amorphous silicon, or a mixture thereof.

24. The article of claim 23, wherein the nanowires are grown on the substrate.

25. The article of claim 23, wherein a portion of the electrolyte is directly linked to the surface of the nanowires.

26. The article of claim 23, wherein a portion of the electrolyte forms a continuous or discontinuous film coating on the surface of the nanowires.

27. The article of claim 23, wherein the nanowires are functionalized with at least one functional group which binds the electrolyte to the nanowires.

28. The article of claim 23, wherein the substrate is porous.