Nanowire-based membrane electrode assemblies for fuel cells

• US 20100233585A1
• Filed: 12/20/2006
• Published: 09/16/2010
• 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, Parce, J. Wallace, Empedocles, Stephen A., Chow, Calvin Y.H.
• Granted Patent: US 7,977,013 B2
• Time in Patent Office: Days
• US Class Current: 429/523
• 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 method of making an anode or cathode electrode for a fuel cell, comprising:

forming nanowires on a growth substrate;

transferring the nanowires from the growth substrate into a fluid suspension;

depositing one or more catalyst metals on the nanowires to form a nanowire supported catalyst; and

spraying or brush painting the nanowire fluid suspension onto a component surface of the fuel cell.

2. The method of claim 1, further comprising mixing a proton conducting material with the plurality of nanowires.

3. The method of claim 2, wherein the proton conducting material comprises an ionomeric resin

4. The method of claim 3, wherein the ionomeric resin comprises a perfluorosulfonic acid/PTFE copolymer.

5. The method of claim 2, wherein the plurality of nanowires are derivatized with at least a first chemical binding moiety which binds the proton conducting material.

6. The method of claim 1, wherein the plurality of nanowires are derivatized with at least a first chemical binding moiety which binds the one or more catalyst metal.

7. The method of claim 1, further comprising filtering the fluid suspension of nanowires to create a porous sheet of interconnected nanowires prior to said spraying or brush painting.

8. The method of claim 1, wherein the nanowires comprise semiconducting, conducting, carbide, nitride, or oxide nanowires.

9. The method of claim 1, further comprising forming a proton exchange membrane fuel cell utilizing the formed electrode, comprising:

spraying or brush painting the nanowire fluid suspension onto a first and/or second bipolar plate or a proton exchange membrane of the fuel cell, adding the first and second bipolar plates on either side of the proton exchange membrane; and

sealing the bipolar plates.

10. A nanowire for use in a fuel cell wherein the nanowire comprises silicon carbide (SiC) having a catalyst metal and/or proton conducting coating deposited thereon.

11. The nanowire of claim 10, wherein the nanowire comprises both a metal catalyst and a proton conducting coating deposited thereon.

12. The nanowire of claim 10, wherein the nanowire comprises a proton conducting coating deposited thereon which comprises a perfluorinated sulfonated hydrocarbon molecule.

13. The nanowire of claim 10, wherein the nanowire is functionalized with a chemical binding moiety which binds the catalyst metal and/or proton conducting coating thereto.

14. The nanowire of claim 10, wherein the nanowire comprises a core which comprises silicon and at least one shell layer which comprises silicon carbide.