Membrane electrode assembly

• US 5,879,828 A
• Filed: 10/10/1997
• Issued: 03/09/1999
• Est. Priority Date: 10/10/1997
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Company
• Inventors: Debe, Mark K., Poirier, Richard J., Wackerfuss, Michael K., Ziegler, Raymond J.
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/948,599
• Time in Patent Office: 515 Days
• Field of Search: 429/42, 429/41, 429/44, 204/280, 204/282, 204/290 R, 204/296, 428/195, 428/201, 428/202, 428/209, 428/221, 428/323, 428/327, 428/336, 428/338, 428/357, 428/364, 428/372, 428/378
• US Class Current: 429/483
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: C25B 9/23 comprising ion-exchange membranes in or on which electrode material is embedded
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/8814 Temporary supports, e.g. decal
• CPC Class Codes: H01M 4/8817 Treatment of supports before application of the catalytic active composition coated porous composites H01M8/0245
• CPC Class Codes: H01M 4/8825 Methods for deposition of the catalytic active composition
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/49112 including laminating of indefinite length material
• CPC Class Codes: Y10T 29/5313 Means to assemble electrical device
• CPC Class Codes: Y10T 29/53135 Storage cell or battery
• CPC Class Codes: Y10T 29/53204 Electrode
• CPC Class Codes: Y10T 428/24851 Intermediate layer is discontinuous or differential
• CPC Class Codes: Y10T 428/2486 with outer strippable or release layer
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/254 Polymeric or resinous material
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/268 : Monolayer with structurally defined element
• CPC Class Codes: Y10T 428/29 : Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2913 : Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2927 : including structurally defined particulate matter
• CPC Class Codes: Y10T 428/2938 : Coating on discrete and individual rods, strands or filaments

Abstract

A membrane electrode assembly is provided comprising an ion conducting membrane and one or more electrode layers that comprise nanostructured elements, wherein the nanostructured elements are in incomplete contact with the ion conducting membrane. This invention also provides methods to make the membrane electrode assembly of the invention. The membrane electrode assembly of this invention is suitable for use in electrochemical devices, including proton exchange membrane fuel cells, electrolyzers, chlor-alkali separation membranes, and the like.

Claims

1. A membrane electrode assembly comprising a) a membrane layer which comprises an electrolyte, and b) at least one electrode layer, said electrode layer comprising nanostructured elements, wherein greater than 0% and less than 99% of the volume of said elements is embedded in said membrane layer.

2. The membrane electrode assembly according to claim 1 wherein greater than 0% and less than 95% of the volume of said elements is embedded in said membrane layer.

3. The membrane electrode assembly according to claim 1 wherein greater than 0% and less than 90% of the volume of said elements is embedded in said membrane layer.

4. The membrane electrode assembly according to claim 1 wherein greater than 0% and less than 50% of the volume of said elements is embedded in said membrane layer.

5. The membrane electrode assembly according to claim 1 wherein the nanostructured elements are less than 1.0 micrometer in length and are loaded with less than 0.1 mg/cm² of a catalyst.

6. A fuel cell comprising the membrane electrode assembly of claim 1.

7. A sensor comprising the membrane electrode assembly of claim 1.

8. A membrane electrode assembly comprising a) a membrane layer which comprises an ion conducting electrolyte, and b) at least one electrode layer, said electrode layer comprising nanoscopic catalyst particles, wherein greater than 0% and less than 99% of said particles contact said membrane layer, and wherein the membrane electrode assembly comprises no additional ion conducting electrolyte external to the membrane.

9. The membrane electrode assembly according to claim 8 wherein greater than 0% and less than 95% of the particles contact said membrane layer.

10. The membrane electrode assembly according to claim 8 wherein greater than 0% and less than 90% of the particles contact said membrane layer.

11. The membrane electrode assembly according to claim 8 wherein greater than 0% and less than 50% of the particles contact said membrane layer.

12. A membrane electrode assembly comprising a) a membrane layer which comprises an electrolyte, and b) at least one electrode layer which comprises nanostructured elements, wherein said electrode layer comprises microtextures.

13. The membrane electrode assembly according to claim 12 wherein said microtextures have an average depth less than about one half times the average thickness of the membrane and greater than about three times the average length of the nanostructured elements.

14. The membrane electrode assembly according to claim 12 wherein said microtextures have an average depth between 5 and 25 micrometers.