# US 2017/0288236 A1 · Method for producing fuel cell catalyst layer

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- Number: US 2017/0288236 A1
- Document ID: US20170288236A1
- Status: Published application
- Kind: A1
- Application number: 15/467,496
- Filed: 2017-03-23
- Published: 2017-10-05
- Earliest claimed: 2016-04-04
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Tatsuya ARAI; Takashi OZAKI
- Web page: https://patentgrep.com/patent/US20170288236A1

## CPC

- H01M 4/925: {supported on carriers, e.g. powder carriers}
- H01M 4/8663: {Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers}
- H01M 4/8828: {Coating with slurry or ink}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A fuel cell catalyst layer includes an SnO2 support usable in a wide range of humidity environments and provides high power generation from low to high loads. A production method includes the steps of preparing a catalyst composite of an SnO2 support and platinum or a platinum alloy supported on a surface thereof, and an ionomer that is a proton-conductive polymer; mixing the catalyst composite, the ionomer and a dispersion medium containing at least water and an alcohol having 3 or 4 carbon atoms where the alcohol content is higher than the water, and where a mass ratio (I/MO)) of the ionomer to the SnO2 support is 0.06 to 0.12, and a solid content of the catalyst composite and the ionomer is 24% by mass or more; and dispersing aggregates of the catalyst composite and the ionomer in the dispersion medium by pulverizing by shear force, while preventing reaggregation of the aggregates by applying force.

## Claims

### Claim 1

A method for producing a fuel cell catalyst layer, the method comprising the steps of:
preparing a catalyst composite that comprises an SnO2 support and platinum or a platinum alloy supported on a surface thereof, and an ionomer that is a proton-conductive polymer;
mixing the catalyst composite, the ionomer and a dispersion medium containing at least water and an alcohol having 3 or 4 carbon atoms where a content ratio of the alcohol is higher than the water, in such conditions that a ratio (I/MO) of a mass (I) of the ionomer to a mass (MO) of the SnO2 support is in a range of from 0.06 to 0.12, and a content of a solid comprising the catalyst composite and the ionomer is 24% by mass or more; and
dispersing aggregates comprising the catalyst composite and the ionomer in the dispersion medium, by pulverizing the aggregates by applying shear force, while preventing reaggregation of the pulverized aggregates by applying force.

### Claim 2 (depends on 1)

The method for producing the fuel cell catalyst layer according to claim 1, wherein, in the mixing step, the ratio (I/MO) of the mass (I) of the ionomer to the mass (MO) of the SnO2 support is in a range of from 0.10 to 0.12.

### Claim 3 (depends on 1)

The method for producing the fuel cell catalyst layer according to claim 1, wherein the alcohol is t-butanol or isopropanol.

### Claim 4 (depends on 1)

The method for producing the fuel cell catalyst layer according to claim 1, wherein a planetary ball mill is used in the dispersing step, or a ball mill or mixer is used in combination with a homogenizer in the dispersing step.

### Claim 5 (depends on 1)

The method for producing the fuel cell catalyst layer according to claim 1, wherein the ionomer is a perfluorocarbon sulfonic acid polymer comprising an acidic functional group and a cyclic group.

### Claim 6 (depends on 1)

The method for producing the fuel cell catalyst layer according to claim 1, wherein the solid content of the catalyst composite and ionomer is 40% by mass or less.