Membrane electrode assemblies

• US 5,910,378 A
• Filed: 10/10/1997
• Issued: 06/08/1999
• Est. Priority Date: 10/10/1997
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Company
• Inventors: Larson, James M., Debe, Mark K., Ziegler, Raymond J., Balsimo, William V., Steinbach, Andrew J.
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/948,627
• Time in Patent Office: 606 Days
• Field of Search: 429/41, 429/40, 429/42, 204/282, 204/283, 204/296, 428/304.4, 428/305.5, 428/306.6, 428/308.4, 428/311.1, 428/315.7
• US Class Current: 429/483
• CPC Class Codes: C25B 9/23 comprising ion-exchange membranes in or on which electrode material is embedded
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8825 Methods for deposition of the catalytic active composition
• CPC Class Codes: H01M 4/8875 Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support
• CPC Class Codes: H01M 4/8878 Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
• CPC Class Codes: H01M 8/0206 Metals or alloys
• CPC Class Codes: H01M 8/0221 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0226 in the form of mixtures
• CPC Class Codes: H01M 8/0239 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0243 in the form of mixtures
• CPC Class Codes: H01M 8/0247 characterised by the form characterised by a channel configuration H01M8/0258
• CPC Class Codes: H01M 8/0271 Sealing or supporting means around electrodes, matrices or membranes
• CPC Class Codes: H01M 8/0273 with sealing or supporting means in the form of a frame
• CPC Class Codes: H01M 8/0297 Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other H01M8/0271 takes precedence
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• 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 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1051 Non-ion-conducting additives, e.g. stabilisers, SiO2 or ZrO2
• CPC Class Codes: H01M 8/109 : thermal other than drying, e.g. sintering
• CPC Class Codes: H01M 8/241 : with solid or matrix-supported electrolytes
• 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: Y10T 156/1084 : of continuous or running length bonded web
• 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 29/49114 : including adhesively bonding
• CPC Class Codes: Y10T 29/49115 : including coating or impregnating
• CPC Class Codes: Y10T 29/49885 : with coating before or during assembling
• CPC Class Codes: Y10T 29/4998 : Combined manufacture including applying or shaping of fluent material
• CPC Class Codes: Y10T 29/49982 : Coating
• CPC Class Codes: Y10T 29/49984 : and casting
• CPC Class Codes: Y10T 29/49988 : Metal casting
• CPC Class Codes: Y10T 29/49989 : Followed by cutting or removing material
• CPC Class Codes: Y10T 29/53135 : Storage cell or battery
• CPC Class Codes: Y10T 29/53139 : including deforming means
• CPC Class Codes: Y10T 29/532 : Conductor
• CPC Class Codes: Y10T 29/53204 : Electrode
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249954 : With chemically effective material or specified gas other than air, N, or carbon dioxide in void-containing component
• CPC Class Codes: Y10T 428/249955 : Void-containing component partially impregnated with adjacent component
• CPC Class Codes: Y10T 428/249958 : Void-containing component is synthetic resin or natural rubbers
• CPC Class Codes: Y10T 428/249962 : Void-containing component has a continuous matrix of fibers only [e.g., porous paper, etc.]
• CPC Class Codes: Y10T 428/249979 : Specified thickness of void-containing component [absolute or relative] or numerical cell dimension

Abstract

Membrane electrode assemblies are described that include an ion conductive membrane a catalyst adjacent to the major surfaces of the ion conductive membrane and a porous particle filled polymer membrane adjacent to the ion conductive membrane. The catalyst can be disposed on the major surfaces of the ion conductive membrane. Preferably, the catalyst is disposed in nanostructures. The polymer film serving as the electrode backing layer preferably is processed by heating the particle loaded porous film to a temperature within about 20 degrees of the melting point of the polymer to decrease the Gurley value and the electrical resistivity. The MEAs can be produced in a continuous roll process. The MEAs can be used to produce fuel cells, electrolyzers and electrochemical reactors.

Claims

1. An electrochemical MEA comprising:

an ion conductive membrane, said membrane having a first and second major surface;

catalyst adjacent to said first and second major surfaces; and

a porous, electrically conductive polymer film adjacent to said ion conductive membrane, said film comprising a polymer matrix and about 45 to about 98 percent by weight electrically conductive particles embedded within said polymer matrix;

wherein the Gurly value of said polymer film is less than about 100 s/50 cc.

2. The electrochemical MEA of claim 1, wherein the Gurley value of said polymer film is less than about 50 s/50 cc.

3. The electrochemical MEA of claim 1, wherein said polymer matrix comprises a polymer selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, poly(tetrafluoroethylene-co-perfluoro-(propyl vinyl ether)) and mixtures thereof.

4. The electrochemical MEA of claim 1, wherein said electrically conductive particles comprise carbon.

5. The electrochemical MEA of claim 1, wherein said porous polymer film has an electrical resistivity of less than about 20 ohm-cm.

6. The electrochemical MEA of claim 1, wherein said catalytic material is disposed at an interface between said ion conductive membrane and said porous, electrically conductive polymer film.

7. The electrochemical MEA of claim 1, wherein said catalytic material is disposed upon at least one of said surfaces of said ion conductive membrane.

8. The electrochemical MEA of claim 1, wherein said catalyst is disposed in nanostructured elements.

9. An electrochemical MEA comprising:

an ion conductive membrane, said membrane having a first and second major surface;

catalyst adjacent to said first and second major surfaces; and

a porous, electrically conductive polymer film adjacent to said ion conductive membrane, said film comprising electrically conductive particles and a porous matrix of fibrillated PTFE fibrils.

10. The electrochemical MEA of claim 9, wherein said catalytic material is disposed at an interface between said ion conductive membrane and said porous, electrically conductive polymer film.

11. The electrochemical MEA of claim 9, wherein said catalytic material is disposed upon at least one major surface of said ion conductive membrane.

12. The electrochemical MEA of claim 9, wherein said conductive particles comprise carbon.

13. The electrochemical MEA of claim 9, wherein said porous polymer film has a Gurley value of less than 50 s/50 cc.

14. The electrochemical MEA of claim 9, wherein said porous polymer film has an electrical resistivity of less than 20 ohm-cm.