Powder for solid oxide fuel cell air electrode and method of manufacturing same

Patent metadata

Field	Value
Publication number	US-2021351416-A1
Application number	US-201917277707-A
Country	US
Kind code	A1
Filing date	Aug 5, 2019
Priority date	Sep 27, 2018
Publication date	Nov 11, 2021
Grant date	—

Abstract

A powder material for an air electrode in a solid oxide fuel cell, the powder material being a powder of a metal composite oxide having a perovskite crystal structure represented by:A11-xA2xBO3-δ,where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and δ is an oxygen deficiency amount. The powder has a specific surface area of 20 m2/g or more, satisfies (Crystallite diameter/Specific surface area-based particle diameter)≥0.3, and contains elements M in an amount of 300 ppm or less in terms of atoms, the elements M being other than the elements A1, A2 and B, and oxygen.

First claim

1 . A powder material for an air electrode in a solid oxide fuel cell, the powder material comprising:
a powder of a metal composite oxide having a perovskite crystal structure represented by a following general formula:
A1 1-x A2 x BO 3-δ ,
where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and δ is an oxygen deficiency amount, the powder having a specific surface area of 20 m 2 /g or more, the powder satisfying (Crystallite diameter/Specific surface area-based particle diameter)≥0.3, and the powder containing elements M in an amount of 300 ppm or less in terms of atoms, the elements M being other than the element A1, the element A2, the element B, and oxygen.

2 . The powder material according to claim 1 , wherein the powder satisfies (Crystallite diameter/Average particle diameter)≥0.05.

3 . The powder material according to claim 1 , wherein
the element A1 is La, the element A2 is Sr, and the element B is at least one selected from the group consisting of Co and Fe.

4 . A method of producing a powder material for an air electrode in a solid oxide fuel cell, the method comprising:
a preparation step of preparing a metal composite oxide having a perovskite crystal structure represented by a following general formula:
A1 1-x A2 x BO 3-δ,
where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, x satisfies 0<x<1, and δ is an oxygen deficiency amount; and a pulverization step of pulverizing the metal composite oxide with aluminum oxide beads, into a powder having a specific surface area of 20 m 2 /g or more and satisfying (Crystallite diameter/Specific surface area-based particle diameter)≥0.3.

5 . The method of producing a powder material according to claim 4 , the method further comprising a preliminary pulverization step of pulverizing the metal composite oxide to have a specific surface area of 2 m 2 /g or more and less than 20 m 2 /g, before the pulverization step.

6 . The method of producing a powder material according to claim 5 , wherein the preparation step includes a step of synthesizing the metal composite oxide by mixing a first compound containing the element A1, a second compound containing the element A2, and a third compound containing the element B, followed by heating at 1250° C. or more.

7 . The method of producing a powder material according to claim 6 , wherein the powder obtained by the pulverization step satisfies (Crystallite diameter/Average particle diameter)≥0.05.

8 . The method of producing a powder material according to claim 7 , wherein the aluminum oxide beads have a purity of 99.9 mass % or more.

9 . The powder material according to claim 2 , wherein
the element A1 is La, the element A2 is Sr, and the element B is at least one selected from the group consisting of Co and Fe.

Assignees

• Sakai Chemical Industry Co

Inventors

• Hirata Norimune
• Yoneda Minoru

Classifications

• H01M2004/8689

  Positive electrodes · 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

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• C01P2002/52

  containing elements as dopants · CPC title

• C01P2002/34

  perovskite-type (ABO3) · CPC title