Efficient reversible electrodes for solid oxide electrolyzer cells
An electrolyzer cell is disclosed which includes a cathode to reduce an oxygen-containing molecule, such as H2O, CO 2 , or a combination thereof, to produce an oxygen ion and a fuel molecule, such as H 2 , CO, or a combination thereof. An electrolyte is coupled to the cathode to transport the oxygen ion to an anode. The anode is coupled to the electrolyte to receive the oxygen ion and produce oxygen gas therewith. In one embodiment, the anode may be fabricated to include an electron-conducting phase having a perovskite crystalline structure or structure similar thereto. This perovskite may have a chemical formula of substantially (Pr( 1-x) La x )(z-y)A′ y BO(3-∂), wherein 0<x<1, 0≦y≦0.5, and 0.8≦z≦1.1. In another embodiment, the cathode includes an electron-conducting phase that contains nickel oxide intermixed with magnesium oxide.
1. An electrolyzer cell comprising:
a cathode to reduce an oxygen-containing molecule to produce an oxygen ion and a fuel molecule;
an electrolyte coupled to the cathode to transport the oxygen ion;
an anode coupled to the electrolyte to receive the oxygen ion to produce oxygen gas therewith, the anode comprising an electron-conducting phase comprising a perovskite having a chemical formula of substantially (Pr (1-x) D x ) (z-y) A′ y BO (3-∂) , wherein 0<x<1, 0≦y≦0.5, 0.8≦z≦1.1, D is selected from the group consisting of La, Ba, and a La—Ba mixture, A′ is an alkaline earth metal, and B is a transition metal; and
wherein the anode further comprises an ion-conducting phase comprising an oxide.
2. The electrolyzer cell of claim 1 , wherein the oxide comprises zirconia doped with at least one of yttrium oxide, ytterbium oxide, calcium oxide, magnesium oxide, scandium oxide, and cerium oxide.
3. The electrolyzer cell of claim 1 , wherein the oxide comprises ceria doped with at least one of yttrium oxide, ytterbium oxide, calcium oxide, magnesium oxide, scandium oxide, and zirconium oxide.
4. The electrolyzer cell of claim 1 , wherein the anode is porous, the porosity thereof being infiltrated with an electrocatalyst.
5. The electrolyzer cell of claim 4 , wherein the electrocatalyst comprises at least one of praseodymium, cobalt, cerium, europium, and other rare earth elements.
6. The electrolyzer cell of claim 1 , wherein the alkaline earth metal comprises at least one of calcium and strontium.
7. The electrolyzer cell of claim 6 , wherein the alkaline earth metal comprises calcium.
8. The electrolyzer cell of claim 1 , wherein the transition metal comprises at least one of manganese, cobalt, and iron.
9. The electrolyzer cell of claim 1 , wherein the cathode comprises an electron-conducting phase comprising at least one of nickel oxide and magnesium oxide.
10. The electrolyzer cell of claim 1 , wherein y is zero such that there is no A′ composition in the perovskite.
11. The electrolyzer cell of claim 1 , wherein D is La.
12. The electrolyzer cell of claim 1 , wherein D is Ba.
13. The electrolyzer cell of claim 1 , wherein the perovskite has the formula (Pr (0.2) La 0.8 )CO 0.8 Fe 0.2 O (3-∂) .
14. An electrolyzer cell comprising:
a cathode to reduce an oxygen-containing molecule to produce an oxygen ion and a fuel molecule;
an electrolyte coupled to the cathode to transport the oxygen ion;
an anode coupled to the electrolyte to receive the oxygen ion to produce oxygen gas therewith, the anode comprising an electron-conducting phase comprising a perovskite having a chemical formula of substantially (Pr (1-x) La x ) (z-y) A′ y BO (3-∂) , wherein 0≦x≦1, 0≦y≦0.5, 0.8≦z≦1.1, A′ is an alkaline earth metal, and B is a transition metal; and
wherein the anode further comprises an ion-conducting phase comprising an oxide.
15. The electrolyzer cell of claim 14 , wherein y is zero such that there is no A′ composition in the perovskite.
16. The electrolyzer cell of claim 14 , wherein the oxide comprises zirconia doped with at least one of yttrium oxide, ytterbium oxide, calcium oxide, magnesium oxide, scandium oxide, and cerium oxide.
17. The electrolyzer cell of claim 14 , wherein the oxide comprises ceria doped with at least one of yttrium oxide, ytterbium oxide, calcium oxide, magnesium oxide, scandium oxide, and zirconium oxide.
18. The electrolyzer cell of claim 14 , wherein the anode is porous, the porosity thereof being infiltrated with an electrocatalyst.
19. The electrolyzer cell of claim 16 , wherein the electrocatalyst comprises at least one of praseodymium, cobalt, cerium, europium, and other rare earth elements.
20. The electrolyzer cell of claim 14 , wherein the cathode comprises an electron-conducting phase comprising at least one of nickel oxide and magnesium oxide.
21. The electrolyzer cell of claim 14 , wherein the alkaline earth metal comprises at least one of calcium and strontium.
22. The electrolyzer cell of claim 14 , wherein the transition metal comprises at least one of manganese, cobalt, and iron.
23. An electrolyzer cell comprising:
a cathode to reduce an oxygen-containing molecule to produce an oxygen ion and a fuel molecule, the cathode comprising an electron conducting phase comprising at least one of nickel oxide and magnesium oxide;
an electrolyte coupled to the cathode to transport the oxygen ion;
an anode coupled to the electrolyte to receive the oxygen ion to produce oxygen gas therewith, the anode comprising an electron-conducting phase comprising a perovskite having a chemical formula of substantially (Pr (1-x) La x ) (z-y) A′ y BO (3-∂) , wherein 0≦x≦1, 0≦y≦0.5, 0.8≦z≦1.1, A′ is an alkaline earth metal, and B is a transition metal; and
wherein the anode further comprises an ion-conducting phase comprising ceria doped with at least one of yttrium oxide, ytterbium oxide, calcium oxide, magnesium oxide, scandium oxide, and zirconium oxide.
24. The electrolyzer cell of claim 23 , wherein the alkaline earth metal comprises strontium.
25. The electrolyzer cell of claim 24 , wherein the transition metal comprises at cobalt and iron.