Chemically sintered composite electrodes and manufacturing processes

Patent metadata

Field	Value
Publication number	US-9583778-B2
Application number	US-88894307-A
Country	US
Kind code	B2
Filing date	Aug 3, 2007
Priority date	Aug 3, 2007
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

An iterative process of depositing on a solid electrolyte a coating of unconnected particles composed of an ionically conductive material. A liquid solution is also applied. The liquid solution includes an inorganic component. The deposited liquid is heated to a temperature sufficient to evaporate or otherwise remove some or all of the volatile components of the liquid solution. Typically the temperature is below 1000° and often at about 850° C. The effect of heating the solution is to cause ion conducting material in the solution to adhere to the surface of the existing ion conducting particles and form connections between these particles. This is understood to create an ion conducting skeletal support structure. Within the intrestices of this skeletal support structure, the step of heating is also understood to result in the deposition of the inorganic component that will begin to form a electron conducting structure. The process of applying the liquid solution and heating may be repeated until a sufficiently thick layer of material is laid over the solid electrolyte to provide the composite electrode structure desired.

First claim

What is claimed is:

1. A method for producing solid oxide fuel cell (SOFC) electrodes on a substrate, the method comprising:
providing the substrate, the substrate including a solid oxide electrolyte or a support structure attached to and supporting the solid oxide electrolyte;
in a first layer step, applying a first layer of individual, unconnected particles to the substrate, wherein the first layer includes a plurality of individual particles composed of oxygen ionically conductive material;
in a second layer step, separate from the first layer step, applying liquid to the first layer, wherein the liquid includes an ionically conductive inorganic component, an electrically conductive inorganic component, and a solvent so that the ionically conductive inorganic component and the electrically conductive inorganic component substantially cover at least a portion of each particle on the substrate, wherein the another layer step applies a different material composition than the first layer step; and
in a third layer step, heating the liquid to a temperature of less than about 1000 degrees Celsius, so as to evaporate the solvent and produce a coating on the particles to form an ionically and electrically conductive layer;
wherein the first layer includes a plurality of the individual, unconnected particles.

2. The method of claim 1 , wherein the inorganic component includes one of Platinum and Lanthanum Strontium Manganate.

3. The method of claim 1 , wherein the substrate has a substrate temperature, and when applying the liquid, the substrate temperature is greater than about 50° C.

4. The method of claim 1 , wherein heating occurs simultaneous with applying the liquid.

5. The method of claim 1 , wherein applying liquid comprises one of painting, screen printing, dip coating, spraying, dispensing from a needle, and jetting.

6. The method of claim 1 , wherein the liquid further comprises a plating solution, and applying the liquid comprises suspending the substrate in a bath of the liquid.

7. The method of claim 1 , wherein the heating includes a first heating and a second heating, and the second heating is hotter than the first heating.

8. The method of claim 7 , wherein the first heating comprises heating to a temperature of about 70° C. and the second heating comprises heating to a temperature of about 450° C.

9. The method of claim 1 , wherein the inorganic component has a weight and the liquid has a total weight including the weight of the inorganic component, and wherein the weight of the inorganic component is less than ten percent of the total weight of the liquid.

10. The method of claim 1 , wherein the first layer has a weight, and the inorganic component has a weight, and wherein the weight of the inorganic component is less than ten percent of the weight of the first layer.

11. The method of claim 1 , wherein the first layer further comprises pores located between the individual particles, and wherein applying the liquid comprises substantially filling the pores with the liquid.

12. The method of claim 1 , wherein the oxygen ion conductive material comprises one of Yttria Stabilized Zirconia, Ceria, or Hafnia.

13. The method of claim 1 , wherein the ionically conductive inorganic component is applied in a second layer and the electronically conductive inorganic component is applied in another layer.

14. The method of claim 13 , further comprising:
heating the second layer to less than about 1000 degrees Celsius.

15. The method of claim 1 , wherein the individual particles of the oxygen ionically conductive material are ionically conductive.

16. The method of claim 1 , wherein the individual particles of the electrically conductive inorganic component are electrically conductive.

17. The method of claim 1 , wherein the first layer further includes a plurality of individual particles comprising electronically conductive particles.

18. The method of claim 1 , further comprising:
applying a second layer to the substrate, wherein the second layer comprises a plurality of individual particles.

19. The method of claim 18 , wherein the first layer is applied to a first portion of the substrate and the second layer is applied to a second portion of the substrate.

20. The method of claim 1 , wherein the liquid is selectively applied to a portion of the substrate.

21. The method of claim 1 , further comprising providing at least one wall coupled to the substrate to provide at least two separate portions of the substrate.

22. The method of claim 1 , further comprising:
providing a mask to form distinct electrodes on the substrate.

23. The method of claim 1 , wherein the temperature is less than about 850° C.

24. The method of claim 1 , wherein the temperature is less than about 500° C.

25. The method of claim 1 , wherein the support structure includes a silicon nitride layer patterned into matrix spaced islands.

26. The method of claim 25 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid.

27. The method of claim 25 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid, diluted with a solvent.

28. The method of claim 25 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid, diluted with a solvent, which includes butoxyethanol.

29. The method of claim 1 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid.

30. The method of claim 1 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid, diluted with a solvent.

31. The method of claim 1 , wherein the electrically conductive inorganic component is provided in the form of a liquid solution that includes hexachloroplatinic acid, diluted with a solvent, which includes butoxyethanol.

32. The method of claim 1 , wherein the liquid includes the electrically conductive inorganic component and a solvent so that the electrically conductive inorganic component substantially cover at least a portion of each particle on the substrate, wherein the another layer step applies a different material composition than the first layer step, and wherein the liquid is heated to a temperature of less than about 1000 degrees Celsius, so as to evaporate the solvent and produce the coating on the ionically conducting particles, so that the electrically conductive inorganic material forms into a matrix of electron conducting pathways formed within the ion-conducting structure, so as to form the ionically and electrically conductive layer.

33. The method of claim 1 , wherein the unconnected particles have the ability to move relative to each other so as to form a skeleton, and wherein in the second layer step and the third layer step, the skeleton is transformed into a compact layer.

34. The method of claim 33 , wherein transformation is done by applying a liquid with other material in it and evaporating a solvent of the liquid by heating so as to result in a chemically sintered layer of the

Assignees

• Schaevitz Samuel B
• Byars Zachary
• Ganeshananthan Ramanan
• Verma Atul
• Rule John
• Bosch Gmbh Robert

Inventors

• Schaevitz Samuel B
• Byars Zachary
• Ganeshananthan Ramanan
• Verma Atul
• Petrovsky Vladimir
• Rule John

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/1097

  Fuel cells applied on a support, e.g. miniature fuel cells deposited on silica supports · CPC title

• Y02E60/525

  Cross-Sectional Technologies · mapped topic

• H01M4/8657

  layered · CPC title

• H01M8/1286

  Fuel cells applied on a support, e.g. miniature fuel cells deposited on silica supports · CPC title