Cathode material and fuel cell

Patent metadata

Field	Value
Publication number	US-10312525-B2
Application number	US-201514819572-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Apr 12, 2013
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

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 %.

First claim

What is claimed is:

1. A fuel cell comprising:
an anode,
a cathode including a perovskite type oxide, the perovskite type oxide being expressed by the general formula ABO 3 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) 3 O 4 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%.

2. 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%.

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

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

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

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

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

8. The fuel cell according to claim 1 , wherein
the (Co,Fe) 3 O 4 is at least one selected from the group consisting of CoFe 2 O 4 , Co 1.5 Fe 1.5 O 4 and Co 2 FeO 4 .

9. The fuel cell according to claim 1 , wherein
the cathode consists essentially of the perovskite type oxide and (Co, Fe) 3 O 4 .

Assignees

• Ngk Insulators Ltd

Inventors

• Ohmori Makoto
• Kobayashi Ayano

Classifications

• C04B2235/3277

  Co3O4 · CPC title

• C04B2235/768

  Perovskite structure ABO3 · CPC title

• C04B2235/3227

  Lanthanum oxide or oxide-forming salts thereof · CPC title

• H01M4/9033 Primary

  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 · CPC title

• C04B2235/80

  Phases present in the sintered or melt-cast ceramic products other than the main phase · CPC title