SOLID OXIDE FUEL CELL

• US 20140162149A1
• Filed: 12/09/2013
• Published: 06/12/2014
• Est. Priority Date: 12/10/2012
• Status: Active Grant

• Current Assignee: Morimura Sofc Technology Co., Ltd.
• Original Assignee: Toto Limited
• Inventors: NIIMI, Hiroshi, ISHIGURO, Akira, ANDO, Shigeru, KAWAKAMI, Akira, SHIMAZU, Megumi, TAKAHASHI, Yuya
• Granted Patent: US 9,515,322 B2
• Time in Patent Office: Days
• US Class Current: 429/405
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 4/8621 containing only metallic or ceramic material, e.g. made by sintering or sputtering
• CPC Class Codes: H01M 4/8652 as mixture
• CPC Class Codes: H01M 4/8828 Coating with slurry or ink
• CPC Class Codes: H01M 4/8885 Sintering or firing
• CPC Class Codes: H01M 4/8889 Cosintering or cofiring of a catalytic active layer with another type of layer
• 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 8/1213 characterised by the electrode/electrolyte combination or the supporting material
• 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

Disclosed is a durable solid oxide fuel cell that is less likely to have a problem of a conventional solid oxide fuel cell that an air electrode containing a peroviskite oxide, when exposed to a reducing atmosphere, is separated at the stop of operation, especially shutdown. The solid oxide fuel cell includes an air electrode that is obtained by firing a compact containing a perovskite oxide and sulfur element. The content of the sulfur element in the air electrode as fresh after firing or before the start of power generation is in the range of 50 ppm to 3,000 ppm. The separation of the air electrode is effectively suppressed at the shutdown operation.

Claims

1. A solid oxide fuel cell comprising a solid electrolyte, a fuel electrode, and an air electrode, wherein

the air electrode comprises a product obtained by firing a compact containing a perovskite oxide and sulfur element and

the content of the sulfur element in the air electrode as fresh after firing or before the start of power generation is 50 ppm to 3,000 ppm.

2. The solid oxide fuel cell according to claim 1, wherein the sulfur element is derived from a sulfur compound, the sulfur compound and the perovskite oxide being independently mixed.

3. The solid oxide fuel cell according to claim 1, wherein the sulfur element is derived from a sulfur compound contained in a starting material employed in preparing the perovskite oxide.

4. The solid oxide fuel cell according to claim 1, wherein the perovskite oxide is lanthanum strontium cobaltite ferrite (LSCF).

5. The solid oxide fuel cell according to claim 1, wherein the content of the sulfur element is 100 ppm to 3,000 ppm.

6. A fuel cell system comprising the solid oxide fuel cell according to claim 1.

7. A method for manufacturing the solid oxide fuel cell according to claim 1, the method comprising:

providing a starting material powder including a perovskite oxide with a sulfur compound added;

dispersing the starting material powder in a solvent to prepare a slurry;

applying the slurry to a solid electrolyte or its precursor, drying the coated solid electrolyte or its precursor, and firing the dried solid electrolyte or its precursor to prepare the air electrode.

8. A method for manufacturing a solid oxide fuel cell according to claim 1, the method comprising:

firing a mixture obtained by adding a sulfur compound to a starting material employed in preparing a perovskite oxide to obtain a sulfur element-containing perovskite oxide;

comminuting the perovskite oxide to obtain a starting material powder;

dispersing the starting material powder in a solvent to prepare a slurry; and

applying the slurry to a solid electrolyte or its precursor, drying the coated solid electrolyte or its precursor, and firing the dried solid electrolyte or its precursor to prepare the air electrode.