Low Temperature Electrolytes for Solid Oxide Cells Having High Ionic Conductivity

Abstract

Some embodiments of the present invention provide solid oxide cells and components thereof having a metal oxide electrolyte that exhibits enhanced ionic conductivity. Certain of those embodiments have two materials, at least one of which is a metal oxide, disposed so that at least some interfaces between the domains of the materials orient in a direction substantially parallel to the desired ionic conductivity.

1 . A method of enhancing ionic conductivity in a metal oxide electrolyte comprising a first material and a metal oxide comprising:
 applying a metal compound to the first material; and   converting at least some of the metal compound to form the metal oxide;   wherein the first material and the metal oxide have an ionic conductivity greater than the bulk ionic conductivity of the first material and of the metal oxide.   
     
     
         2 . The method of  claim 1 , wherein the first material comprises crystalline material. 
     
     
         3 . The method of  claim 2 , wherein the crystalline material comprises nanocrystalline material. 
     
     
         4 . The method of  claim 1 , wherein the first material comprises a metal oxide. 
     
     
         5 . The method of  claim 1 , wherein the first material is chosen from strontium titanate, titania, alumina, zirconia, yttria-stabilized zirconia, alumina-doped yttria-stabilized zirconia, iron-doped zirconia, magnesia, ceria, samarium-doped ceria, gadolinium-doped ceria, and combinations thereof. 
     
     
         6 . The method of  claim 5 , wherein the first material is chosen from alumina, titania, zirconia, yttria-stabilized zirconia, alumina-doped yttria-stabilized zirconia, iron-doped zirconia, magnesia, ceria, samarium-doped ceria, gadolinium-doped ceria, and combinations thereof. 
     
     
         7 . The method of  claim 1 , wherein the first material comprises mica. 
     
     
         8 . The method of  claim 1 , wherein the metal oxide is chosen from strontium titanate, titania, alumina, zirconia, yttria-stabilized zirconia, alumina-doped yttria-stabilized zirconia, iron-doped zirconia, magnesia, ceria, samarium-doped ceria, gadolinium-doped ceria, and combinations thereof. 
     
     
         9 . The method of  claim 8 , wherein the metal oxide is chosen from alumina, titania, zirconia, yttria-stabilized zirconia, alumina-doped yttria-stabilized zirconia, iron-doped zirconia, magnesia, ceria, samarium-doped ceria, gadolinium-doped ceria, and combinations thereof. 
     
     
         10 . The method of  claim 1 , wherein the first material comprises strontium titanate, and the metal oxide comprises yttria-stabilized zirconia. 
     
     
         11 . The method of  claim 10 , wherein the yttria-stabilized zirconia comprises from about 10 mol % to about 20 mol % yttria. 
     
     
         12 .- 13 . (canceled) 
     
     
         14 . The method of  claim 1 , wherein the first material comprises magnesia, and the metal oxide comprises yttria-stabilized zirconia. 
     
     
         15 . The method of  claim 1 , wherein the first material comprises titania, and the metal oxide comprises yttria-stabilized zirconia. 
     
     
         16 . The method of  claim 1 , wherein the first material comprises strontium titanate, and the metal oxide comprises iron-doped zirconia. 
     
     
         17 . The method of  claim 1 , wherein the first material comprises samarium-doped ceria, and the metal oxide comprises ceria. 
     
     
         18 . (canceled) 
     
     
         19 . A metal oxide electrolyte comprising:
 a first material and a metal oxide, wherein the metal oxide is formed by applying a metal compound to the first material; and   converting at least some of the metal compound to form the metal oxide,   wherein the first material and the metal oxide have an ionic conductivity greater than the bulk ionic conductivity of the first material and of the metal oxide.   
     
     
         20 . A method for forming a metal oxide electrolyte, comprising:
 applying a metal compound to a first material in powder form; and   converting at least some of the metal compound to form a metal oxide, thereby forming the metal oxide electrolyte;   wherein the metal oxide electrolyte has an ionic conductivity greater than the bulk ionic conductivity of the first material and of the metal oxide.   
     
     
         21 . The method of  claim 20 , wherein the first material in powder form comprises strontium titanate, and the metal oxide comprises yttria-stabilized zirconia. 
     
     
         22 . The method of  claim 20 , wherein the first material in powder form comprises mica, and the metal oxide comprises yttria-stabilized zirconia, gadolinium-doped ceria, alumina, or a combination thereof. 
     
     
         23 .- 24 . (canceled) 
     
     
         25 . A method for forming a metal oxide electrolyte, comprising:
 applying a first metal compound to a substrate;   converting at least some of the first metal compound to form a first metal oxide on the substrate;   applying a second metal compound to the substrate comprising the first metal oxide; and   converting at least some of the second metal compound to form a second metal oxide on the substrate comprising the first metal oxide,   thereby forming the metal oxide electrolyte;   wherein the metal oxide electrolyte has an ionic conductivity greater than the bulk ionic conductivity of the first metal oxide and of the second metal oxide.   
     
     
         26 . The method of  claim 25 , further comprising
 applying additional first metal compound to the substrate comprising the first metal oxide and the second metal oxide; and   converting at least some of the additional first metal compound to form additional first metal oxide.   
     
     
         27 . The method of  claim 26 , further comprising
 applying additional second metal compound to the additional first metal oxide; and   converting at least some of the additional second metal compound to form additional second metal oxide.   
     
     
         28 .- 41 . (canceled) 
     
     
         42 . A solid oxide cell, comprising:
 an inner tubular electrode having an outer surface;   an outer electrode; and   a metal oxide electrolyte adapted to provide ionic conductivity between the inner tubular electrode and the outer electrode;   wherein the metal oxide electrolyte comprises a plurality of thin sheets oriented substantially perpendicular to the outer surface of the inner tubular electrode, and a metal oxide contacting the thin sheets.