# US 10,312,525 B2 · Cathode material and fuel cell

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- Number: US 10,312,525 B2
- Document ID: US10312525B2
- Status: Granted
- Kind: B2
- Application number: 14/819,572
- Filed: 2015-08-06
- Published: 2015-12-03
- Granted: 2019-06-04
- Earliest claimed: 2013-04-12
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Makoto Ohmori; Ayano Kobayashi
- Web page: https://patentgrep.com/patent/US10312525B2

## CPC

- H01M 4/9033: {Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites}
- C04B 35/01: based on oxide ceramics
- C04B 35/2641: {Compositions containing one or more ferrites of the group comprising rare earth metals and one or more ferrites of the group comprising alkali metals, alkaline earth metals or lead}
- H01M 4/8652: {as mixture}
- H01M 8/1213: characterised by the electrode/electrolyte combination or the supporting material
- H01M 8/1246: the electrolyte consisting of oxides
- C04B 2235/3213: Strontium oxides or oxide-forming salts thereof
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3227: Lanthanum oxide or oxide-forming salts thereof
- C04B 2235/3272: Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
- C04B 2235/3274: Ferrites
- C04B 2235/3275: Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
- C04B 2235/3277: Co3O4
- C04B 2235/3279: Nickel oxides, nickalates, or oxide-forming salts thereof
- C04B 2235/763: Spinel structure AB2O4
- C04B 2235/768: Perovskite structure ABO3
- C04B 2235/77: Density
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/83: Ferrites containing Fe2+
- H01M 4/8657: {layered}
- H01M 2008/1293: {Fuel cells with solid oxide electrolytes}
- H01M 2300/0071: Oxides
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A cathode material used in an anode and a cathode contains (Co,Fe)3O4 and a perovskite type oxide that is expressed by the general formula ABO3 and includes at least one of La and Sr at the A site. A content ratio of (Co,Fe)3O4 in the cathode material is at least 0.23 wt % and no more than 8.6 wt %.

## Claims

### Claim 1

A fuel cell comprising:
an anode,
a cathode including a perovskite type oxide, the perovskite type oxide being expressed by the general formula ABO3 and including at least one of La and Sr at the A site, and
a solid electrolyte layer disposed between the anode and the cathode,
the cathode including a solid electrolyte layer-side region within 3 micrometers from a surface near to the solid electrolyte layer,
the solid electrolyte layer-side region including a main phase comprising the perovskite type oxide, and a secondary phase comprising (Co,Fe)3O4 that includes both Co and Fe,
an occupied area ratio of the secondary phase in a cross section of the solid electrolyte layer-side region being no more than 9.5%, and
an occupied area ratio of the main phase in a cross section of the solid electrolyte layer-side region being at least 87.5%.

### Claim 2 (depends on 1)

The fuel cell according to claim 1, wherein
the occupied area ratio of the secondary phase in the solid electrolyte layer-side region is at least 0.25%.

### Claim 3 (depends on 1)

The fuel cell according to claim 1, wherein
a density of the secondary phase is smaller than a density of the main phase.

### Claim 4 (depends on 1)

The fuel cell according to claim 1, wherein
the perovskite type oxide is LSCF.

### Claim 5 (depends on 2)

The fuel cell according to claim 2, wherein
a density of the secondary phase is smaller than a density of the main phase.

### Claim 6 (depends on 2)

The fuel cell according to claim 2, wherein
the perovskite type oxide is LSCF.

### Claim 7 (depends on 3)

The fuel cell according to claim 3, wherein
the perovskite type oxide is LSCF.

### Claim 8 (depends on 1)

The fuel cell according to claim 1, wherein
the (Co,Fe)3O4 is at least one selected from the group consisting of CoFe2O4, Co1.5Fe1.5O4 and Co2FeO4.

### Claim 9 (depends on 1)

The fuel cell according to claim 1, wherein
the cathode consists essentially of the perovskite type oxide and (Co, Fe)3O4.