Method for solid oxide fuel cell fabrication

1. A method of making a solid oxide fuel cell (SOFC), comprising:

forming a first sublayer of an anode electrode on a first side of a planar solid oxide electrolyte by screen printing;

drying the first sublayer of the anode electrode at a first temperature that is between 50° C. and 80° C.;

forming a second sublayer of the anode electrode on the dried first sublayer of the anode electrode by screen printing prior to firing the first sublayer of the anode electrode;

forming a cathode electrode of a different material than the first and second sublayers of the anode electrode on a second side of the planar solid oxide electrolyte;

burning out the anode and cathode electrodes at a second temperature that is between 1100° C. and 1200° C., for a time period sufficient to burn out a binder; and

simultaneously sintering the first and second sublayers of the anode electrode and the cathode electrode at a third temperature that is greater than the second temperature, such that the anode and cathode electrodes are sintered at substantially the same temperature,

wherein the burning out is performed in a first atmosphere and the sintering is performed in a second atmosphere, the first atmosphere having a higher oxygen content than the second atmosphere, due to oxygen enrichment of the first atmosphere; and

wherein:

the first sublayer of the anode electrode comprises a cermet comprising a nickel containing phase and a doped ceria containing phase;

the second sublayer of the anode electrode comprises a cermet comprising a nickel containing phase and a doped ceria containing phase; and

the first sublayer of the anode electrode contains a lower ratio of the nickel containing phase to the ceramic phase than the second sublayer of the anode electrode;

the cathode electrode comprises an electrically conductive perovskite material; and

the anode electrode does not contain the electrically conductive perovskite material.

2. The method of claim 1 , wherein the third temperature is between 1200° C. and 1300° C.

3. The method of claim 2 , wherein the steps of burning out and sintering are performed in the same furnace.

4. The method of claim 1 , wherein the step of forming the cathode electrode comprises:

forming a first sublayer of a cathode electrode on the second side of the planar solid oxide electrolyte;

drying the first sublayer of the cathode electrode; and

forming a second sublayer of the cathode electrode on the dried first sublayer of the cathode electrode prior to sintering the first sublayer of the cathode electrode.

5. The method of claim 1 , further comprising drying the second sublayer of the anode electrode prior to the burning out of the anode and the cathode electrodes.

6. The method of claim 1 , wherein the step of forming the first sublayer of the anode electrode comprises:

placing the electrolyte into a slotted cassette;

installing the cassette into an elevator which positions the electrolyte onto conveyor;

transporting the electrolyte to a screen printing tool plate;

aligning the electrolyte into position on the screen printing tool plate;

applying a hold down vacuum to hold the electrolyte on the screen printing tool plate; and

screen printing the first sublayer of the anode electrode using an ink comprising 80 to 93% by weight solids.

7. The method of claim 6 , wherein the step of drying the first sublayer of the anode electrode comprises placing the electrolyte on a belt, transporting the electrolyte to a heating zone, and drying the first sublayer of the anode electrode using a infrared heating lamp.

8. The method of claim 1 , wherein the step of forming the cathode electrode comprises screen printing the cathode electrode on the second side of the planar solid oxide electrolyte.

9. The method of claim 1 , wherein the first sublayer of the anode electrode is dried at a peak temperature that is between 50° C. and 80° C. prior to forming the second sublayer of the anode electrode on the first sublayer of the anode electrode.

10. A method of making a solid oxide fuel cell (SOFC), comprising:

forming a first sublayer of an anode electrode on a first side of a planar solid oxide electrolyte by screen printing;

drying the first sublayer of the anode electrode at a first temperature that is between 50° C. and 80° C.;

forming a second sublayer of the anode electrode on the dried first sublayer of the anode electrode by screen printing prior to firing the first sublayer of the anode electrode;

forming a cathode electrode of a different material than the first and second sublayers of the anode electrode on a second side of the planar solid oxide electrolyte;

burning out the anode and cathode electrodes in a first atmosphere and at a second temperature that is higher than the first temperature, for a time period sufficient to burn out a binder; and

simultaneously sintering the first and second sublayers of the anode electrode and the cathode electrode in a second atmosphere and at a third temperature that is greater than the second temperature, such that the anode and cathode electrodes are sintered at substantially the same temperature,

wherein the first atmosphere has a higher oxygen content than the second atmosphere; and,

wherein:

the burning out is conducted under sufficient air flow to oxidize and clear binder off-gassed species;

the first sublayer of the anode electrode comprises a cermet comprising a nickel containing phase and a doped ceria containing phase;

the second sublayer of the anode electrode comprises a cermet comprising a nickel containing phase and a doped ceria containing phase;

the cathode electrode comprises an electrically conductive perovskite material; and

the anode electrode does not contain the electrically conductive perovskite material.