Cobalt-substituted perovskite compounds for solid oxide electrochemical cells
Oxygen electrodes are provided, comprising a perovskite compound having Formula (I), Sr(Ti 1-x Fe x-y Co y )O 3-δ wherein 0.90≥x≥0.40 and 0.02≥y≥0.30. Electrochemical devices comprising such oxygen electrodes are also provided, comprising a counter electrode in electrical communication with the oxygen electrode, and a solid oxide electrolyte between the oxygen electrode and the counter electrode. Methods of using such electrochemical devices are also provided, comprising exposing the oxygen electrode to a fluid comprising O 2 under conditions to induce the reaction O 2 +4e − →2O 2− , or to a fluid comprising O 2− under conditions to induce the reaction 2O 2− →O 2 +4e − .
1. An oxygen electrode comprising a perovskite compound having Formula IA, Sr(Ti 0.3 Fe 0.7-x Co x )O 3-δ wherein 0.04≥x≥0.15.
2. The electrode of claim 1 , wherein 0.07≥x≥0.15.
3. The electrode of claim 1 , wherein x=0.07.
4. The electrode of claim 1 , wherein x=0.15.
5. The electrode of claim 1 , further comprising a plurality of praseodymium oxide nanoparticles distributed on a surface of the perovskite compound.
6. An electrochemical device comprising the oxygen electrode of claim 1 , a counter electrode in electrical communication with the oxygen electrode, and a solid oxide electrolyte between the oxygen electrode and the counter electrode.
7. The electrochemical device of claim 6 , wherein 0.07≥x≥0.15.
8. The electrochemical device of claim 6 , wherein x=0.07.
9. The electrochemical device of claim 6 , wherein x=0.15.
10. A method comprising exposing the oxygen electrode of the electrochemical device of claim 6 to a fluid comprising O 2 under conditions to induce the reaction O 2 +4e − →2O 2− , or to a fluid comprising O 2− under conditions to induce the reaction 2O 2− →O 2 +4e − .
11. The method of claim 10 , wherein the conditions include an operating temperature of no more than 700° C.
12. The method of claim 10 , wherein the conditions include an operating temperature of no more than 600° C.
13. The method of claim 12 , wherein the oxygen electrode exhibits a constant polarization resistance value (R p ) while carrying out the method over a time period of at least 1000 hours.