Fuel cell incorporating a reinforced membrane

• US 5,795,668 A
• Filed: 11/10/1994
• Issued: 08/18/1998
• Est. Priority Date: 11/10/1994
• Status: Expired due to Term

• Current Assignee: The Chemours Company FC, LLC (The Chemours Company)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Banerjee, Shoibal
• Primary Examiner(s): Willis, Jr., Prince
• Assistant Examiner(s): CHANEY, CAROL DIANE
• Application Number:
  US08/339,167
• Time in Patent Office: 1,377 Days
• Field of Search: 429/12, 429/33
• US Class Current: 429/492
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 8/0289 Means for holding the electrolyte solid polymer electrolytes H01M8/1018
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1044 Mixtures of polymers, of which at least one is ionically conductive
• CPC Class Codes: H01M 8/1053 consisting of layers of polymers with at least one layer being ionically conductive
• CPC Class Codes: H01M 8/106 characterised by the chemical composition of the porous support
• CPC Class Codes: H01M 8/1062 characterised by the physical properties of the porous support, e.g. its porosity or thickness
• CPC Class Codes: H01M 8/1067 characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell and a battery with a reinforced polymeric ion exchange membrane are disclosed. The membrane comprises (a) a porous support layer, preferably of fluorine-containing polymer, and (b) an ion exchange resin, preferably a fluorinated ion exchange layer(s) supported on one or both sides of the porous support layer. The total thickness of the membrane is preferably from 20 to 500 μm. The membrane has low fuel crossover, high electric conductivity and high mechanical strength. The membrane may especially be used in a direct methanol fuel cell.

Claims

1. A fuel cell comprising anode and cathode compartments partitioned by a reinforced polymeric ion exchange membrane, said membrane consisting essentially of

(a) at least one ion exchange polymer selected from the group consisting of perfluorinated polymers with side chains containing the group --CF₂ CF₂ SO₂ F, and

(b) a porous support layer comprising a microporous film of perfluorinated polymer selected from the group consisting of polytetrafluoroethylene and copolymers of tetrafluoroethylene with ##STR5## m=0 to 15, n=1 to 15, said support layer being fully embedded in said membrane.

2. The fuel cell of claim 1 wherein said porous support layer has a pore diameter from about 0.05 to 10 μ

m, a porosity of about 50-95% and a thickness of about 10 to 200 μ

m.

3. The fuel cell of claim 1 wherein the porous support layer has interior surfaces which are substantially hydrophilic.

4. The fuel cell of claim 1 wherein the total thickness of the membrane is about 20 to 550 μ

m.

5. The fuel cell of claim 1 wherein the transport of methanol in a 4% by weight aqueous solution across the membrane at 60°

C. is less than 4×

10 ^-5 ml methanol/minute ·

cm ².

6. The fuel cell of claim 1 wherein the fuel cell operates with a liquid hydrocarbon fuel.

7. The fuel cell of claim 6 wherein the fuel cell operates with a fuel of methanol.

8. The fuel cell of claim 1 wherein fuel transport is reduced by at least 10% compared to the fuel transport in a fuel cell having said membrane with no porous support layer.

9. A fuel cell comprising anode and cathode compartments partitioned by a reinforced polymeric ion exchange membrane, said membrane comprising

(a) at least one ion exchange polymer, and

(b) a porous support layer comprising a polymer having an aliphatic ring structure containing fluorine.

10. A fuel cell comprising anode and cathode compartments partitioned by a reinforced polymeric ion exchange membrane, said membrane consisting essentially of

(a) at least one ion exchange polymer selected from the group consisting of perfluorinated polymers with side chains containing the group --CF₂ CF₂ SO₂ F, and

(b) a porous support layer comprising a microporous film of perfluorinated polymer selected from the group consisting of polytetrafluoroethylene and copolymers of tetrafluoroethylene with ##STR6## m=0 to 15, n=1 to 15, said porous support layer being on one surface of the membrane and said surface facing the cathode compartment of the fuel cell.