Solid Oxide Electrochemical Devices Having an Improved Electrode
An electrode with improved resistance to Cr poisoning comprising A x B 3-x O 4 , wherein A is selected from the group consisting of Mn, Co, Fe, Cr, Cu, V, and Ni and B is selected from the group consisting of Mn, Co, Fe, Cr, Cu, V, and Ni and a solid oxide electrochemical device comprising the same. A method for making a solid oxide electrochemical device comprising the above-described electrode.
1 . An electrode for use in a solid oxide electrochemical device comprising A x B 3-x O 4 , wherein A and B are selected from the group consisting of Mn, Co, Fe, Cr, Cu, V, and Ni.
2 . An electrode as in claim 1 further comprising at least one ionic conducting electrolyte material.
3 . An electrode as in claim 2 wherein the at least one ionic conducting electrolyte material is selected from the group consisting of doped zirconia, doped ceria, doped lanthanum gallate, and doped Ba(Sr)Ce(Zr)O 3 .
4 . An electrode as in claim 1 further comprising at least one catalyst.
5 . An electrode as in claim 4 wherein the at least one catalyst is a precious metal.
6 . An electrode as in claim 5 wherein the precious metal is selected from the group consisting of Pt, Pd, Ag, Ru, and Rh.
7 . An electrode as in claim 4 wherein the at least one catalyst is a conducting ceramic.
8 . An electrode as in claim 1 wherein x ranges from an amount greater than 0 and less than 3.
9 . An electrode as in claim 1 wherein x ranges from about 0.5 to about 2.5.
10 . An electrode as in claim 1 wherein x equals 1.5.
11 . An electrode as in claim 1 wherein the solid oxide electrochemical device is a solid oxide fuel cell.
12 . An electrode as in claim 1 wherein the solid oxide electrochemical device is a solid oxide electrolyzer.
13 . An electrode as in claim 1 wherein the solid oxide electrochemical device is a electrochemical pump.
14 . A solid oxide fuel cell comprising:
a cathode comprising A x B 3-x O 4 , wherein A and B are selected from the group consisting of Mn, Co, Fe, Cr, Cu, V, and Ni;
an anode;
electrolyte disposed between the anode and the cathode; and
a metallic interconnect electrically connecting the cathode of one cell to the anode of a second cell.
15 . The solid oxide electrochemical device as in claim 14 wherein x ranges from about 0 to about 3.
16 . The solid oxide electrochemical device as in claim 14 wherein x ranges from about 0.5 to about 2.5.
17 . A method of making a solid oxide electrochemical device comprising a first electrode comprising A x B 3-x O 4 wherein A and B are selected from the group consisting of Mn, Co, Fe, Cr, Cu, V, and Ni, a second electrode, an electrolyte disposed between said electrodes, and a metallic interconnect, the method comprising the steps of:
brazing the second electrode to the metallic interconnect in a reducing atmosphere or vacuum environment; and
oxidizing the solid oxide electrochemical device in a oxidizing atmosphere to convert any A a O y , B b O z , A, and B formed during the brazing step back to A x B 3-x O 4 .
18 . A method as in claim 17 wherein the oxidizing atmosphere is an environment with a temperature from about 700° C. to about 900° C.
19 . A method as in claim 17 wherein the step of brazing further comprises reducing the second electrode while exposing both electrodes to a reducing atmosphere.
20 . A method as in claim 18 wherein the second electrode comprises NiO and Yttria-stabilized zirconia.