Fabrication processes for solid state electrochemical devices

Patent metadata

Field	Value
Publication number	US-11283084-B2
Application number	US-201815968917-A
Country	US
Kind code	B2
Filing date	May 2, 2018
Priority date	May 3, 2017
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

This disclosure provides systems, methods, and apparatus related to electrode structures. In one aspect, a method includes: providing an electrode layer comprising a ceramic, the ceramic being porous; providing a catalyst precursor, the catalyst precursor being a cathode catalyst precursor or an anode catalyst precursor; infiltrating the catalyst precursor in a first side of the electrode layer; after the infiltrating operation, heating the electrode layer to about 750° C. to 950° C., the catalyst precursor forming a catalyst, the catalyst being a cathode catalyst or an anode catalyst; infiltrating the catalyst precursor in the first side of the electrode layer; after the infiltrating operation, heating the electrode layer to about 300° C. to 700° C., the catalyst precursor forming the catalyst, the catalyst being the cathode catalyst or the anode catalyst.

First claim

What is claimed is:

1. A method of fabricating an electrode structure, the method comprising:
(a) providing an electrode layer comprising a ceramic, the ceramic being porous;
(b) providing a catalyst precursor, the catalyst precursor being a cathode catalyst precursor or an anode catalyst precursor;
(c) infiltrating the catalyst precursor in a first side of the electrode layer, wherein a second side of the electrode layer is covered by a mask that prevents infiltration of the catalyst precursor;
(d) after operation (c), heating the electrode layer to a first temperature within a first temperature range of about 750° C. to 950° C., the catalyst precursor forming a catalyst, the catalyst being a cathode catalyst or an anode catalyst, wherein the first temperature increases interparticle contact of the catalyst, and the increased interparticle contact improves electronic and/or ionic conductivity;
(e) after operation (d), further infiltrating the catalyst precursor in the first side of the electrode layer; and
(f) after operation (e), heating the electrode layer to a second temperature within a second temperature range of about 300° C. to 700° C. provided that the second temperature is lower than the first temperature, the catalyst precursor forming the catalyst, the catalyst being the cathode catalyst or the anode catalyst, wherein the second temperature does not increase interparticle contact of the catalyst, and wherein any subsequent heat treatments are performed at temperatures at or below the second temperature range that do not increase interparticle contact of the catalyst and preserve a surface area of the catalyst.

2. The method of claim 1 , wherein during one or more of operation (c) or operation (e) when the catalyst precursor is infiltrated in the first side of the electrode layer the catalyst precursor is heated to about 90° C. to 95° C.

3. The method of claim 1 , wherein operations of infiltrating the catalyst precursor in the first side of the electrode layer are performed in a vacuum of about 600 millibar to 800 millibar.

4. The method of claim 1 , further comprising:
before operation (d), heating the electrode layer to about 40° C. to 90° C.; and
before operation (f), heating the electrode layer to about 40° C. to 90° C.

5. The method of claim 1 , further comprising:
after operation (f), further infiltrating the catalyst precursor in the first side of the electrode layer; and
heating the electrode layer to about 300° C. to 700° C., wherein the further infiltrating and the heating are performing until a specified amount of the catalyst is deposited on the electrode layer.

6. The method of claim 1 , wherein operations (d) and (f) are performed for about 30 minutes to 5 hours.

7. The method of claim 1 , wherein the ceramic comprises stabilized zirconia or doped ceria.

8. The method of claim 1 , wherein the catalyst precursor comprises a metal salt.

9. The method of claim 1 , wherein the catalyst precursor comprises citric acid.

10. The method of claim 1 , wherein excess catalyst is removed from the electrode layer after operations (d) and (f).

11. The method of claim 1 , wherein the electrode layer is about 10 microns to 250 microns thick.

12. The method of claim 1 , wherein the method forms a structure comprising a catalyst layer that is about 10 microns to 100 microns thick.

13. The method of claim 1 , wherein heating the electrode layer to the second temperature causes the catalyst to have at least a target surface area.

14. A method of fabricating an electrode structure, the method comprising:
(a) providing an electrode layer comprising a ceramic, the ceramic being porous;
(b) providing a cathode catalyst precursor and an anode catalyst precursor;
(c) infiltrating the cathode catalyst precursor in a first side of the electrode layer, wherein a second side of the electrode layer is covered by a mask that prevents infiltration of the cathode catalyst precursor;
(d) removing the mask and infiltrating the anode catalyst precursor in the second side of the electrode layer;
(e) after operations (c) and (d), heating the electrode layer to a first temperature within a first temperature range of about 750° C. to 950° C., the cathode catalyst precursor forming a cathode catalyst and the anode catalyst precursor forming an anode catalyst wherein the first temperature increases interparticle contact of the catalysts, and the increased interparticle contact improves electronic and/or ionic conductivity;
(f) after operation (e), further infiltrating the cathode catalyst precursor in the first side of the electrode layer;
(g) after operation (e), further infiltrating the anode catalyst precursor in the second side of the electrode layer; and
(h) after operations (f) and (g), heating the electrode layer to a second temperature within a second temperature range of about 300° C. to 700° C. provided that the second temperature is lower than the first temperature, the cathode catalyst precursor forming the cathode catalyst and the anode catalyst precursor forming the anode catalyst, wherein the second temperature does not increase interparticle contact of the catalysts, and wherein any subsequent heat treatments are performed at temperatures at or below the second temperature range that do not increase interparticle contact of the catalysts and preserve a surface area of the catalysts.

15. The method of claim 14 , wherein the method forms a structure comprising a cathode catalyst layer that is about 10 microns to 100 microns thick, an anode catalyst layer that is about 10 microns to 100 microns thick, and an electrolyte layer that is about 5 microns to 50 microns thick disposed between the cathode catalyst layer and the anode catalyst layer.

16. The method of claim 15 , wherein the cathode catalyst layer and the anode catalyst layer are the same thickness.

17. The method of claim 14 , wherein the cathode catalyst precursor and the anode catalyst precursor are the same composition.

18. The method of claim 14 , wherein the electrode layer is about 10 microns to 250 microns thick.

19. The method of claim 14 , wherein the cathode catalyst precursor comprises a first metal salt, and wherein the anode catalyst precursor comprises a second metal salt.

20. The method of claim 14 , further comprising:
after operation (f), further infiltrating the cathode catalyst precursor in the first side of the electrode layer; and
heating the electrode layer to about 300° C. to 700° C., wherein the infiltrating and the heating are performing until a specified amount of the cathode catalyst is deposited on the electrode layer.

21. The method of claim 14 , further comprising:
after operation (g), further infiltrating the anode catalyst precursor in the second side of the electrode layer; and
heating the electrode layer to about 300° C. to 700° C., wherein the infiltrating and the heating are performing until a specified amount of the anode catalyst is deposited on the electrode layer.

Assignees

• Univ California

Inventors

• Tucker Michael C
• Dogdibegovic Emir

Classifications

• H01M4/885

  followed by reduction of the catalyst salt precursor · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M8/1007

  with both reactants being gaseous or vaporised (H01M8/12 takes precedence) · CPC title

• H01M4/8882 Primary

  Heat treatment, e.g. drying, baking · CPC title