Method for fabricating membrane eletrode assemblies
OwnerMark J. Hampden-Smith, Toivo T. Kodas +6inventors
InventorsMark J. Hampden-Smith, Toivo T. Kodas, Plamen Atanassov, Klaus Kunze, Paul Napolitano, Rimple Bhatia, David E. Dericotte, Paolina Atanassova
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Abstract
Electrocatalyst powders and methods for producing electrocatalyst powders, such as carbon composite electrocatalyst powders. The powders have a well-controlled microstructure and morphology. The method includes forming the particles from an aerosol of precursors by heating the aerosol to a relatively low temperature, such as not greater than about 400° C.
Claims81
A powder batch comprising composite electrocatalyst particles, said electrocatalyst particles comprising a support phase and an active species phase dispersed on said support phase, wherein said support phase comprises primary support particles having an average size of from about 10 to about 100 nanometers, wherein the average cluster size of said active species phase is not greater than about 20 nanometers and wherein said electrocatalyst particles have a surface area of at least about 90 m2/g.
A powder batch of metal-carbon composite electrocatalyst particles, said electrocatalyst particles comprising a carbon support phase and a metal active species phase dispersed on said support phase, wherein said support phase comprises primary carbon particles having an average size of from about 20 to about 40 nanometers and wherein the average cluster size of said metallic active species phase is not greater than about 10 nanometers.
A powder batch of composite electrocatalyst particles, said electrocatalyst particles comprising a carbon support phase and a metal oxide active species phase dispersed on said support phase, wherein said support phase comprises primary support particles having an average size of from about 20 to about 40 nanometers and wherein the average cluster size of said metal oxide active species phase is not greater than about 10 nanometers.
A method for the production of composite electrocatalyst particles, comprising the steps of:
- a) generating an aerosol of droplets from a precursor liquid wherein said precursor liquid comprises at least a first precursor to a support phase and at least a second precursor to an active species phase;
- b) moving said droplets in a carrier gas;
- and
- c) heating said droplets to remove liquid therefrom and react at least one of said first and second precursors to form composite electrocatalyst particles wherein said active species phase is dispersed on said support phase.
A method for the production of composite electrocatalyst particles, comprising the steps of:
- a) forming a liquid precursor comprising a particulate carbon precursor and at least a first precursor to an active species phase;
- b) generating an aerosol of droplets from said liquid precursor;
- and
- c) heating said aerosol of droplets in a spray dryer at a conversion temperature of not greater than about 400° C. to form electrocatalyst particles wherein said first precursor is converted to an active species phase dispersed on said support phase.
A method for making particles including a polymer phase, comprising the steps of:
- a) forming a liquid-containing precursor comprising at least a first precursor component and a polymer emulsion;
- b) generating an aerosol of precursor droplets from said liquid-containing precursor;
- and
- c) heating said aerosol of precursor droplets to remove liquid therefrom and form said particles.
A electrode assembly, comprising:
- a) a current collector disposed on a gas diffusion layer;
- and
- b) an electrocatalyst layer disposed on said current collector, wherein said electrocatalyst layer comprises carbon particles and electrocatalyst particles dispersed throughout a polymer matrix wherein the hydrophobicity of said polymer matrix decreases with increased distance from said current collector.
An electrode assembly, comprising:
- a) a gas diffusion layer;
- b) a current collector disposed on said gas diffusion layer;
- and
- c) a gradient functional layer disposed over said current collector, wherein said gradient functional layer comprises carbon particles and electrocatalyst particles and wherein the concentration of carbon particles relative to electrocatalyst particles decreases with distance from said current collector.
Dependencies are inferred from the claim text.