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 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;
disposing 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 (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.
2. The method 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 method of claim 1 , wherein a thickness of the functional layer ranges from approximately 1 μm to approximately 10 μm.
4. The method of claim 1 , wherein the functional layer contains cobalt at a composition ranging from approximately 0.5 mol % to 5 mol %.
5. The method of claim 4 , wherein at least a portion of the solid electrolyte layer does not contain cobalt.
6. The method of claim 1 , wherein a composition of the functional layer is different from a composition of the solid electrolyte layer.
7. The method of claim 6 , wherein the composition of the functional layer is different from a composition of the anode layer.
8. The method of claim 1 , wherein a composition of the functional layer is different from a composition of the anode layer.
9. The method of claim 1 , wherein the anode layer comprises a composite comprising nickel and yttria-stabilized zirconia.
10. The method of claim 1 , wherein the solid electrolyte layer is disposed over the anode layer before the functional layer is disposed over the solid electrolyte layer.
11. The method of claim 1 , wherein the anode layer is provided by tape casting.
12. The method of claim 1 , wherein disposing the solid electrolyte layer over the anode layer comprises laminating the solid electrolyte layer to the anode layer.
13. The method of claim 1 , further comprising providing the solid electrolyte layer before disposing the solid electrolyte layer over the anode layer.
14. The method of claim 13 , wherein providing the solid electrolyte layer comprises tape casting.
15. The method of claim 1 , further comprising annealing the solid oxide fuel cell after the cathode layer is disposed over the functional layer.
16. The method of claim 1 , wherein at least a portion of the solid oxide fuel cell is annealed at a temperature ranging from 800° C. to 1100° C. for a time period ranging from 0.5 hour to 5 hours after the solid electrolyte layer is disposed over the anode layer.
17. The method of claim 1 , further comprising annealing the functional layer and the cathode layer together after the cathode layer is disposed over the functional layer.
18. The method of claim 17 , wherein the annealing is performed at a temperature ranging from 800° C. to 1100° C. for a time period ranging from 0.5 hour to 5 hours.
19. The method of claim 1 , wherein the solid electrolyte comprises at least one of yttria-stabilized zirconia, scandia-stabilized zirconia, lanthanum strontium magnesium gallate, samarium-doped ceria, or gadolinium-doped ceria.
20. The method 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.