Fuel cell cathode containing a perovskite oxide

• US 10,644,327 B2
• Filed: 01/04/2018
• Issued: 05/05/2020
• Est. Priority Date: 07/07/2015
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Fujisaki, Shinji, Yamamura, Yoshihiko, Ryu, Takashi, Ohmori, Makoto
• Primary Examiner(s): Laios, Maria
• Application Number:
  US15/862,277
• Publication Number:
  US 20180131007A1
• Time in Patent Office: 852 Days
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3246 Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia
• CPC Class Codes: C04B 2235/3275 Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
• CPC Class Codes: C04B 2235/3279 Nickel oxides, nickalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/72 Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/725 Metal content
• CPC Class Codes: C04B 2235/768 Perovskite structure ABO3
• CPC Class Codes: C04B 35/2608 Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
• CPC Class Codes: C04B 35/488 Composites
• CPC Class Codes: C04B 35/505 based on yttrium oxide
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8668 Binders
• CPC Class Codes: 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
• CPC Class Codes: H01M 8/1253 the electrolyte containing zirconium oxide
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A fuel cell cathode contains a perovskite oxide as a main component. The perovskite oxide is expressed by the general formula ABO₃ and including La and Sr at the A site. A solid electrolyte layer is disposed between an anode and the cathode. The cathode has a surface on an opposite side to the solid electrolyte layer. A first ratio of a Sr concentration relative to an La concentration is less than or equal to 4 times a second ratio of the Sr concentration relative to the La concentration. The first ratio is detected by the use of X-ray photoelectron spectroscopy on the surface of the cathode. The second ratio of a Sr concentration relative to a La concentration is detected by the use of X-ray photoelectron spectroscopy on an exposed surface exposed by surface processing of the surface and positioned within 5 nm of the surface in relation to a direction of thickness.

Claims

1. A fuel cell comprising:

an anode,

a cathode containing a perovskite oxide as a main component, the perovskite oxide expressed by the general formula ABO₃ and including La and Sr at the A site, and

a solid electrolyte layer disposed between the anode and the cathode,

the cathode having a surface on opposite side to the solid electrolyte layer, and

a first ratio of a Sr concentration relative to an La concentration being from 1.2 to 4 times a second ratio of the Sr concentration relative to the La concentration,

the first ratio being detected by use of X-ray photoelectron spectroscopy on the surface of the cathode, the second ratio of a Sr concentration relative to a La concentration being detected by use of X-ray photoelectron spectroscopy on an exposed surface,

the exposed surface being exposed by surface processing of the surface,

the exposed surface being positioned within 5 nm of the surface in relation to a direction of thickness of the cathode.

2. The fuel cell according to claim 1, wherein a total amount of Ba, Ca, Na and K in the A site of the perovskite oxide is less than or equal to 2000 ppm.