Fuel cell membrane electrode assemblies with improved power outputs and poison resistance
OwnerCarlos A. Cavalca, James H. Arps +1inventors
InventorsCarlos A. Cavalca, James H. Arps, Mahesh Murthy
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Abstract
An electrode-membrane combination for use in a fuel cell and providing improved power outputs and resistance to poisoning. Multiple embodiments are described which generally involve use of a vapor deposited zone or layer of one or more catalytically active metals. Vapor deposition can be carried out by, for example, sputtering or physical vapor deposition.
Claims79
An electrode-membrane combination comprising:
- at least one reactant diffusive, electronically conductive electrode, wherein the electrode is substantially free of first catalytically active metal;
- and
- at least one ionically conductive membrane contacting the electrode to form an electrode-membrane interfacial region,
- wherein the interfacial region comprises at least one zone consisting essentially of at least two second catalytically active metals, different from each other, and having a zone thickness of about 3 angstroms to about 5,000 angstroms.
An electrode-membrane combination comprising:
- at least one reactant diffusive, electronically conductive electrode, wherein the electrode is substantially free of first catalytically active metal;
- and
- at least one ionically conductive membrane contacting the electrode to form an electrode-membrane interfacial region,
- wherein the interfacial region consists essentially of at least one zone comprising at least two second catalytically active metals, different from each other, and having a zone loading of about 0.001 mg metal/cm2 to about 0.7 mg metal/cm2.
An electrode membrane combination in which noble metal in the combination is substantially concentrated at an electrode membrane interface for fuel cell catalysis, the combination consisting essentially of (i) at least one electronically conductive electrode which allows for fuel cell reactant transport and which is surface enriched with at least one ionically conductive polymer, and (ii) at least one ionically conductive membrane which contacts the electrode at the electrode surface which is enriched with ionically conductive polymer, thereby forming an electrode membrane interfacial region, wherein a vapor deposited layer comprising at least two vapor deposited noble metals is disposed at the interfacial region.
A membrane electrode assembly for use in a solid polymer electrolyte fuel cell which has enhanced resistance to poisoning comprising two electrodes sandwiching a layer of solid polymer electrolyte to form two membrane electrode interfacial regions,
- wherein the solid polymer electrolyte layer is air impermeable and has a thickness less than about 75 microns,
- wherein the electrode is catalyzed with a vapor deposited zone consisting essentially of a composition of at least two noble metals which is formulated to enhance poison resistance during fuel cell operation.
A membrane electrode assembly prepared by the combination of steps comprising:
- providing assembly elements including (i) at least one reactant diffusive, electronically conductive electrode which comprises at least one ionically conductive polymer but which is substantially free of a first catalytically active metal, and (ii) at least one ionically conductive membrane;
- depositing onto at least one of the assembly elements a zone consisting essentially of at least two second catalytically active metals having a zone thickness of about 3 angstroms to about 5,000 angstroms, wherein the zone deposition is (i) a direct deposition onto the assembly element, or (ii) an indirect deposition onto the assembly element wherein the deposited zone is first deposited onto a substrate and then transferred from the substrate onto the assembly element, and
- optionally, assembling the membrane electrode assembly from the assembly elements.
Dependencies are inferred from the claim text.