Titanate and metal interconnects for solid oxide fuels cells

Abstract

A solid oxide fuel cell (SOFC) includes a plurality of sub-cells. Each sub-cell includes a first electrode in fluid communication with a source of oxygen gas, a second electrode in fluid communication with a source of a fuel gas, and a solid electrolyte between the first electrode and the second electrode. The SOFC further includes an interconnect between the sub-cells. In one embodiment, the SOFC has a first surface in contact with the first electrode of each sub-cell and a second surface that is in contact with the second electrode of each sub-cell; and the interconnect consists essentially of a doped M-titanate based perovskite, wherein M is an alkaline earth metal. In another embodiment, the interconnect includes a first layer in contact with the first electrode of each sub-cell, and a second layer in contact with the second electrode of each sub-cell. The first layer includes an electrically conductive material selected from the group consisting of an metal, a metal alloy and a mixture thereof. The second layer includes a doped M-titanate based perovskite, wherein M is an alkaline earth metal. A solid oxide fuel cell described above is formed by connecting each of the sub-cells with an interconnect described above.

1 . A solid oxide fuel cell, comprising;
 a) a plurality of sub-cells, each sub-cell including:
 i) a first electrode in fluid communication with a source of oxygen gas; 
 ii) a second electrode in fluid communication with a source of a fuel gas; and 
 iii) a solid electrolyte between the first electrode and the second electrode; and 
   b) an interconnect between the sub-cells, the interconnect having a first surface in contact with the first electrode of each sub-cell and a second surface that is in contact with the second electrode of each sub-cell, the interconnect consisting essentially of a doped M-titanate based perovskite, wherein M is an alkaline earth metal.   
   
   
       2 . The solid oxide fuel cell of  claim 1 , wherein each sub-cell further includes a first gas channel in fluid communication with the oxygen gas source and with the first electrode, and a second gas channel in fluid communication with the fuel gas source and with the second electrode. 
   
   
       3 . The solid oxide fuel cell of  claim 2 , wherein the first electrode at least in part defines the first gas channel, and the second electrode at least in part defines the second gas channel. 
   
   
       4 . The solid oxide fuel cell of  claim 1 , wherein each of the first and second electrodes is porous. 
   
   
       5 . The solid oxide fuel cell of  claim 4 , wherein the interconnect is substantially planar. 
   
   
       6 . The solid oxide fuel cell of  claim 1 , wherein the M-titanate based perovskite is selected from the group consisting of Sr-titanate, Ca-titanate, Ba-titanate and Mg-titanate. 
   
   
       7 . The solid oxide fuel cell of  claim 6 , wherein the interconnect includes an n-doped Sr-titanate or n-doped Ca-titanate. 
   
   
       8 . The solid oxide fuel cell of  claim 7 , wherein the interconnect includes a Sr-titanate doped with at least one dopant selected from the group consisting of La, Y, Nb, Mn, V, Cr, W, Mo and Si. 
   
   
       9 . The solid oxide fuel cell of  claim 1 , wherein the solid electrolyte includes at least one material selected from the group consisting of ZrO 2  based material, CeO 2  based material and lanthanide-gallate based material. 
   
   
       10 . The solid oxide fuel cell of  claim 1 , wherein the first electrode includes a La-manganate based material. 
   
   
       11 . The solid oxide fuel cell of  claim 1 , wherein the second electrode includes a nickel cermet. 
   
   
       12 . The solid oxide fuel cell of  claim 1 , wherein the thickness of each of the first and second electrodes of at least one of the cells is in a range of between about 1 mm and about 2 mm. 
   
   
       13 . The solid oxide fuel cell of  claim 12 , wherein the thickness of the interconnect is in a range of between about 10 μm and about 1,000 μm. 
   
   
       14 . The solid oxide fuel cell of  claim 13 , wherein the thickness of the interconnect is in a range of between about 10 μm and about 200 μm. 
   
   
       15 . The solid oxide fuel cell of  claim 14 , wherein the thickness of the interconnect is in a range of between about 50 μm and about 200 μm. 
   
   
       16 . The solid oxide fuel cell of  claim 1 , wherein the cells are connected with each other in series. 
   
   
       17 . A method of forming a solid oxide fuel cell cell that includes a plurality of sub-cells, comprising the step of connecting each of the sub-cells with an interconnect, wherein each sub-cell includes:
 i) a first electrode in fluid communication with a source of oxygen gas,   ii) a second electrode in fluid communication with a source of a fuel gas, and   iii) a solid electrolyte between the first electrode and the second electrode, and   
     wherein the interconnect consists essentially of a doped M-titanate based perovskite, wherein M is an alkaline earth metal, the interconnect having a first surface in contact with the first electrode of each cell and a second surface that is in contact with the second electrode of each sub-cell. 
   
   
       18 . A solid oxide fuel cell, comprising;
 a) a plurality of sub-cells, each sub-cell including:
 i) a first electrode in fluid communication with a source of oxygen gas; 
 ii) a second electrode in fluid communication with a source of a fuel gas; and 
 iii) a solid electrolyte between the first electrode and the second electrode; and 
   b) an interconnect between the sub-cells, the interconnect including:
 i) a first layer that includes an electrically conductive material selected from the group consisting of a metal, a metal alloy and a mixture of metals, wherein the first layer is in contact with the first electrode of each sub-cell; and 
 ii) a second layer that includes a doped M-titanate based perovskite, wherein M is an alkaline earth metal, and wherein the second layer is in contact with the second electrode of each sub-cell. 
   
   
   
       19 . The solid oxide fuel cell of  claim 18 , wherein each sub-cell further includes a first gas channel in fluid communication with the oxygen gas source, and a second gas channel in fluid communication with the fuel gas source. 
   
   
       20 . The solid oxide fuel cell of  claim 19 , wherein the first electrode at least in part defines the first gas channel, and the second electrode at least in part defines the second gas channel. 
   
   
       21 . The solid oxide fuel cell of  claim 18 , wherein each of the first and second electrodes is porous. 
   
   
       22 . The solid oxide fuel cell of  claim 21 , wherein the interconnect is substantially planar. 
   
   
       23 . The solid oxide fuel cell of  claim 18 , wherein the doped M-titanate based perovskite is selected from the group consisting of a doped Sr-titanate, a doped Ca-titanate, a doped Ba-titanate and a doped Mg-titanate. 
   
   
       24 . The solid oxide fuel cell of  claim 23 , wherein the doped M-titanate based perovskite includes an n-doped Sr-titanate or n-doped Ca-titanate. 
   
   
       25 . The solid oxide fuel cell of  claim 24 , wherein the doped M-titanate based perovskite includes a Sr-titanate doped with at least one dopant selected from the group consisting of La, Y, Nb, Mn, V, Cr, W, Mo and Si. 
   
   
       26 . The solid oxide fuel cell of  claim 18 , wherein the solid electrolyte includes at least one material selected from the group consisting of ZrO 2  based material, CeO 2  based material and lanthanide-gallate based material. 
   
   
       27 . The solid oxide fuel cell of  claim 18 , wherein the first electrode includes a La-manganate based material. 
   
   
       28 . The solid oxide fuel cell of  claim 18 , wherein the second electrode includes a Ni cermet. 
   
   
       29 . The solid oxide fuel cell of  claim 18 , wherein the first layer of the interconnect includes at least one material selected from the group consisting of Cr-based alloys, ferritic steels, Ni-based super alloys and Ni—Fe—Y 2 O 3  alloy. 
   
   
       30 . The solid oxide fuel cell of  claim 18 , wherein the thickness of each of the first and second electrodes of at least one of the cells is in a range of between about 1 mm and about 2 mm. 
   
   
       31 . The solid oxide fuel cell of  claim 30 , wherein the thickness of the interconnect is in a range of between about 10 μm and about 1,000 μm. 
   
   
       32 . The solid oxide fuel cell of  claim 31 , wherein the thickness of the interconnect is in a range of between about 10 μm and about 200 μm. 
   
   
       33 . The solid oxide fuel cell of  claim 32 , wherein the thickness of the interconnect is in a range of between about 50 μm and about 200 μm. 
   
   
       34 . A method of forming a solid oxide fuel cell that includes a plurality of sub-cells, comprising the step of connecting each of the sub-cells with an interconnect, wherein each sub-cell includes:
 i) a first electrode in fluid communication with a source of oxygen gas,   ii) a second electrode in fluid communication with a source of a fuel gas, and   iii) a solid electrolyte between the first electrode and the second electrode, and   wherein the interconnect includes:   i) a first layer of an electrically conductive metal, a metal alloy or a mixture of metals, wherein the first layer is in contact with the first electrode of each cell; and   ii) a second layer that includes a doped M-titanate based perovskite, wherein M is an alkaline earth metal, and wherein the second layer is in contact with the second electrode of each sub-cell.