Membrane-electrode-assembly with solid polymer electrolyte

• US 20020071980A1
• Filed: 05/31/2001
• Published: 06/13/2002
• Est. Priority Date: 05/31/2000
• Status: Active Grant

• Current Assignee: Japan Gore-Tex Inc (W.L. Gore and Associates)
• Original Assignee: Japan Gore-Tex Inc (W.L. Gore and Associates)
• Inventors: Fujibayashi, Fusaki, Aimu, Masanori, Tabata, Katsuyuki
• Granted Patent: US 6,723,464 B2
• Time in Patent Office: Days
• US Class Current: 429/30
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8807 Gas diffusion layers
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A membrane-electrode-assembly with a solid polymer electrolyte, wherein a laminated structure is obtained by a process in which a membrane/catalyst layer conjugate produced by bonding a first catalyst layer containing a catalyst and an ion-conducting resin to a solid polymer electrolyte membrane, and a gas diffusion layer/catalyst layer conjugate produced by forming a second catalyst layer containing a catalyst and an ion-conducting resin on one side of a gas diffusion layer consisting of a gas-permeable electroconductive sheet material are laminated at least on the anode or cathode side such that the first catalyst layer and second catalyst layer face each other.

Claims

1. A solid polymer electrolyte membrane-electrode-assembly comprising an anode-side gas diffusion layer, an anode catalyst region, a solid polymer electrolyte membrane, a cathode catalyst region, and a cathode-side gas diffusion layer in a sequential arrangement, wherein either the anode catalyst region or the cathode catalyst region or both comprise

(a) at least two catalyst layers wherein one catalyst layer has a side attached to said solid polymer electrolyte membrane and another catalyst layer has a side attached to one of said cathode-side or anode-side gas diffusion layers, and wherein an interface between said two catalyst layers lies between the solid polymer electrolyte and said one of the gas diffusion layers;

(b) wherein said catalyst layers each comprise at least one catalyst and at least one ion-conducting material; and

(c) wherein said at least one catalyst in each of said at least two catalyst layers comprise substantially the same material.

2. A solid polymer electrolyte membrane-electrode-assembly as defined in claim 1, wherein the ion-conducting material in at least one of said catalyst layers comprises an ion conducting polymer.

3. A solid polymer electrolyte membrane-electrode-assembly as defined in claim 1, wherein one of said catalyst layers is bonded to one of said cathode-side or anode-side gas diffusion layers via a carbon-based particle layer comprising carbon-based particles and a fluororesin.

4. A solid polymer electrolyte membrane-electrode-assembly as defined in claim 1, wherein said at least one catalyst comprises particles of a noble metal supported on carbon-based particles.

5. A solid polymer electrolyte membrane-electrode-assembly as defined in claim 1, wherein said cathode-side and anode-side gas diffusion layers are selected from the group consisting of a carbon fiber woven fabric, a carbon fiber nonwoven fabric, carbon felt, carbon paper, and any of the above having a coating of a fluororesin containing electroconductive particles.

7. A fuel cell comprising at least one polymer electrolyte membrane-electrode assembly as defined in claim 1.

8. An electrolysis cell comprising at least one polymer electrolyte membrane-electrode-assembly as defined in claim 1.

6. A method for manufacturing a membrane-electrode-assembly with a solid polymer electrolyte, an anode-side gas diffusion layer, an anode catalyst layer, a solid polymer electrolyte membrane, a cathode catalyst layer, and a cathode-side gas diffusion layer in a sequential arrangement, wherein said method comprises the steps of:

preparing a membrane/catalyst layer conjugate by bonding a first catalyst layer containing a catalyst and an ion-conducting resin to said solid polymer electrolyte membrane;

preparing a gas diffusion layer/catalyst layer conjugate by forming a second catalyst layer containing a catalyst and an ion-conducting resin on one side of said gas diffusion layer; and

forming a two-layer catalyst region by joining the membrane/catalyst layer conjugate and the gas diffusion layer/catalyst layer conjugate such that the first catalyst layer and the second catalyst layer face each other, with said two-layer catalyst region being used as either the anode catalyst layer or cathode catalyst layer.