Solid oxide fuel cells with cathode functional layers
In various embodiments, a solid oxide fuel cell features a functional layer for reducing interfacial resistance between the cathode and the solid electrolyte.
1. A solid oxide fuel cell comprising:
a cathode;
a solid electrolyte for conducting oxygen ions from the cathode to an anode;
an anode for reacting oxygen ions from the solid electrolyte with a hydrogen-containing fuel; and
a functional layer disposed between the cathode and the solid electrolyte,
wherein the solid electrolyte consists of at least one of samarium-doped ceria, gadolinium-doped ceria, yttria-doped ceria, neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
2. The solid oxide fuel cell of claim 1 , wherein the functional layer comprises at least one of cobalt-doped gadolinium-doped ceria or cobalt-doped samarium-doped ceria.
3. The solid oxide fuel cell of claim 1 , wherein the cathode comprises at least one of lanthanum strontium cobalt ferrite, lanthanum strontium manganite, lanthanum strontium cobaltite, barium strontium cobalt ferrite, samarium strontium cobaltite, samarium-doped ceria, or gadolinium-doped ceria.
4. The solid oxide fuel cell of claim 1 , wherein the anode comprises a composite comprising nickel and yttria-stabilized zirconia.
5. The solid oxide fuel cell of claim 1 , wherein a thickness of the functional layer ranges from approximately 1 μm to approximately 10 μm.
6. The solid oxide fuel cell of claim 1 , wherein the functional layer contains cobalt at a composition ranging from approximately 0.5 mol % to 5 mol %.
7. A method of electrochemically converting a hydrogen-containing fuel to electricity, at an operating temperature, using a solid oxide fuel cell comprising (i) a cathode, (ii) an anode, (iii) a solid electrolyte disposed between the anode and the cathode, and (iv) a functional layer disposed between the cathode and the solid electrolyte, wherein a thickness of the functional layer is selected from the range of 0.1 μm to 20 μm, the method comprising:
selecting as the operating temperature a temperature less than 550° C. and greater than 400° C. when the thickness of the functional layer is less than 5 μm;
selecting as the operating temperature a temperature greater than 550° C. when the thickness of the functional layer is greater than 5 μm;
ionizing oxygen at the cathode, thereby producing oxygen ions;
conducting the oxygen ions from the cathode to the anode; and
reacting the oxygen ions with the fuel at the anode at the operating temperature, thereby generating electricity,
wherein the solid electrolyte consists of at least one of samarium-doped ceria, gadolinium-doped ceria, yttria-doped ceria, neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
8. The method of claim 7 , wherein (i) the thickness of the functional layer is greater than 5 μm, and (ii) the operating temperature is less than 750° C.
9. The method of claim 7 , wherein the functional layer comprises at least one of cobalt-doped gadolinium-doped ceria or cobalt-doped samarium-doped ceria.
10. The method of claim 7 , wherein the functional layer contains cobalt at a composition ranging from approximately 0.5 mol % to 5 mol %.
11. The method of claim 7 , wherein the solid electrolyte comprises at least one of samarium-doped ceria, gadolinium-doped ceria, yttria-doped ceria, neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
12. A method of fabricating a solid oxide fuel cell, the method comprising:
providing an anode layer;
disposing a solid electrolyte layer over the anode layer;
selecting a thickness of a functional layer based at least in part on an intended temperature of operation of the solid oxide fuel cell;
depositing the functional layer over the solid electrolyte layer; and
disposing a cathode layer over the functional layer, thereby forming the solid oxide fuel cell,
wherein the solid electrolyte comprises at least one of samarium-doped ceria, gadolinium-doped ceria, yttria-doped ceria, neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
13. The method of claim 12 , wherein the thickness of the functional layer is selected as 5 μm or less when the intended temperature of operation is less than 550° C.
14. The method of claim 12 , wherein the thickness of the functional layer is selected as 5 μm or greater when the intended temperature of operation is greater than 550° C.
15. The method of claim 12 , wherein the functional layer comprises at least one of cobalt-doped gadolinium-doped ceria or cobalt-doped samarium-doped ceria.
16. The method of claim 12 , wherein a thickness of the functional layer ranges from approximately 1 μm to approximately 10 μm.
17. The method of claim 12 , wherein the functional layer contains cobalt at a composition ranging from approximately 0.5 mol % to 5 mol %.
18. The solid oxide fuel cell of claim 1 , wherein the solid electrolyte consists of at least one of neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
19. The method of claim 12 , wherein (i) the thickness of the functional layer is selected as 5 μm or less when the intended temperature of operation is less than 550° C., and (ii) the thickness of the functional layer is selected as 5 μm or greater when the intended temperature of operation is greater than 550° C.
20. The method of claim 12 , wherein the solid electrolyte consists of at least one of samarium-doped ceria, gadolinium-doped ceria, yttria-doped ceria, neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
21. The method of claim 12 , wherein the solid electrolyte comprises at least one of neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
22. The method of claim 12 , wherein the solid electrolyte consists of at least one of neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
23. The method of claim 7 , wherein the solid electrolyte consists of at least one of neodymium-doped ceria, praseodymium-doped ceria, or lanthanum-doped ceria.
24. The method of claim 10 , wherein at least a portion of the solid electrolyte does not contain cobalt.
25. The method of claim 17 , wherein at least a portion of the solid electrolyte does not contain cobalt.
26. The method of claim 7 , wherein a composition of the functional layer is different from a composition of the solid electrolyte.
27. The method of claim 12 , wherein a composition of the functional layer is different from a composition of the solid electrolyte.
28. The method of claim 27 , wherein the composition of the functional layer is different from a composition of the anode layer.
29. The method of claim 12 , wherein a composition of the functional layer is different from a composition of the anode layer.