Solid oxide fuel cell articles and methods of forming

Patent metadata

Field	Value
Publication number	US-9368823-B2
Application number	US-201213708773-A
Country	US
Kind code	B2
Filing date	Dec 7, 2012
Priority date	Dec 7, 2011
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A solid oxide fuel cell (SOFC) article including a SOFC unit cell having a functional layer of an average thickness of not greater than about 100 μm, wherein the functional layer has a first type of porosity having a vertical orientation, and the first type of porosity has an aspect ratio of length:width, the width substantially aligned with a dimension of thickness of the functional layer.

First claim

What is claimed is:

1. A solid oxide fuel cell (SOFC) article comprising:
an SOFC unit cell comprising a functional layer having an average thickness of not greater than about 100 μm,
wherein the functional layer comprises a first type of pores having:
an aspect ratio of length:width, wherein the length is greater than the width and a dimension of the length defines a pore axis, the pore axis forming an angle that is greater than about 45 degrees from a horizontal axis defining a functional layer width; and
a vertical orientation with respect to the horizontal axis, wherein the first type of pores is present in an amount of at least 20% of the total volume of porosity of the functional layer.

2. The SOFC article of claim 1 , wherein the first type of pores is present in an amount of at least about 50% of the total volume of porosity of the functional layer.

3. The SOFC article of claim 1 , wherein the first type of pores has an aspect ratio of length:width, wherein the length is greater than the width and a dimension of the length is substantially aligned with thickness of the functional layer.

4. The SOFC article of claim 1 , further comprising a second type of pores having a random orientation.

5. The SOFC article of claim 4 , further comprising a third type of pores having a horizontal orientation.

6. The SOFC article of claim 1 , wherein the functional layer comprises at least about 5 vol % porosity for the total volume of the functional layer.

7. The SOFC article of claim 1 , wherein the first type of pores has an average pore size that is not greater than about 25 μm.

8. The SOFC article of claim 1 , wherein the functional layer comprises not greater than about 45 vol % porosity for the total volume of the functional layer.

9. The SOFC article of claim 1 , wherein the average thickness of the functional layer is at least about 1 μm.

10. The SOFC article of claim 1 , wherein the SOFC unit cell further comprises a first electrode comprising a cathode, wherein the cathode is in direct contact with the functional layer, and wherein the cathode comprises a bulk layer portion having a porosity that is greater than a porosity of the functional layer.

11. The SOFC article of claim 1 , wherein the SOFC unit cell further comprises a dense layer overlying the functional layer.

12. The SOFC article of claim 1 , wherein the functional layer is disposed between an electrode and a dense layer.

13. The SOFC article of claim 1 , wherein the angle is greater than about 50 degrees from the horizontal axis.

14. The SOFC article of claim 1 , wherein the functional layer comprises a vertical axis corresponding to a direction of force that is applied during a pressing operation to form the SOFC unit cell, wherein the vertical axis is perpendicular to the horizontal axis, wherein the vertical axis extends in a direction parallel to a thickness of the functional layer.

15. The SOFC article of claim 14 , wherein the pressing operation includes a hot pressing operation.

16. A solid oxide fuel cell (SOFC) article comprising:
a SOFC unit cell comprising a functional layer having an average thickness of not greater than about 100 microns, wherein a portion of a porosity of the functional layer comprises:
a first type of pores having:
an aspect ratio of length:width of at least about 1.1:1, wherein a dimension of the length defines a pore axis, the pore axis forming an angle that is greater than about 45 degrees from a horizontal axis defining a functional layer width; and
a vertical orientation with respect to the horizontal axis,
wherein the first type of pores is present in an amount of at least 20% of the total volume of porosity of the functional layer; and

a second type of pores having a non-vertical orientation with respect to the horizontal axis of the functional layer.

17. The SOFC article of claim 16 , wherein the aspect ratio of length:width is at least about 1.2:1.

18. The SOFC article of claim 16 , wherein the first type of pores is present in an amount of at least about 50% of the total volume of porosity of the functional layer.

19. A method of forming a solid oxide fuel cell SOFC article, the method comprising:
forming a green functional layer having a content of pore forming agents; and
uniaxial hot pressing the green functional layer to form a finished functional layer under transformation conditions selected from the group of conditions consisting of temperature, pressure, time, and atmosphere, wherein a significant portion of pores formed from the pore forming agents vertically oriented with respect to a horizontal axis during uniaxial hot pressing,
wherein the finished functional layer comprises an average thickness of not greater than about 100 μm and a first type of pores, wherein the first type of pores;
has an aspect ratio of length:width, wherein the length is greater than the width and a dimension of the length defines a pore axis, the pore axis forming an angle that is greater than about 45 degrees from a horizontal axis defining a functional layer width;
has a vertical orientation with respect to the horizontal axis; and
is present in an amount of at least 20% of the total volume of porosity of the functional layer.

20. The method of claim 19 , wherein the content of the pore forming agents have a median size of less than about 20 μm; and wherein the finished functional layer comprises an average thickness of not greater than about 100 μm.

Assignees

• Mohanram Aravind
• Saint Gobain Ceramics

Inventors

• Mohanram Aravind

Classifications

• H01M4/861

  with a gradient in the porosity · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M8/1246 Primary

  the electrolyte consisting of oxides · CPC title

• H01M8/1253

  the electrolyte containing zirconium oxide · CPC title

• H01M4/9033

  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 title