Solid oxide electrolyte materials for electrochemical cells

Abstract

Materials for electrochemical cells are provided. BaZr?0.4#191Ce?0.4#191M?0.2#1910?3#191 compounds, where M represents one or more rare earth elements, are provided for use as electrolytes. PrBa?0.5#191Sr?0.5#191Co?2-x#191Fe?x#191O?5+#1916 is provided for use as a cathode. Also provided are electrochemical cells, such as protonic ceramic fuel cells, incorporating the compounds as electrolytes and cathodes.

What is claimed is: 
     
         1 . A compound having the formula BaZr 0.4 Ce 0.4 M 0.2 O 3 , where M represents one or more rare earth elements. 
     
     
         2 . The compound of  claim 1 , having the formula BaZr 0.4 Ce 0.4 Y 0.2−x Yb x O 3 , where 0≤x≤0.2. 
     
     
         3 . The compound of  claim 2 , where x=0.1. 
     
     
         4 . The compound of  claim 1 , having the formula BaZr 0.4 Ce 0.4 Ho 0.2 O 3 . 
     
     
         5 . A cell comprising: a cathode, an anode, and a solid oxide electrolyte between the anode and the cathode, the solid oxide electrolyte comprising a compound having the formula BaZr 0.4 Ce 0.4 M 0.2 O 3 , where M represents one or more rare earth elements. 
     
     
         6 . The cell of  claim 5 , the compound having the formula BaZr 0.4 Ce 0.4 Y 0.2−x Yb x O 3 , where 0≤x≤0.2. 
     
     
         7 . The cell of  claim 6 , where x=0.1. 
     
     
         8 . The cell of  claim 5 , the compound having the formula BaZr 0.4 Ce 0.4 Ho 0.2 O 3 . 
     
     
         9 . The cell of  claim 5 , wherein the cathode comprises a strontium cobalt ferrite perovskite. 
     
     
         10 . The cell of  claim 9 , wherein the cathode comprises PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ . 
     
     
         11 . The cell of  claim 5 , wherein the anode comprises a cermet. 
     
     
         12 . A cell comprising: a cathode, an anode, and a solid electrolyte between the anode and the cathode, the cathode comprising PrBa 0.5 Sr 0.5 Co 2−x Fe x O 5+δ , where 0.4≤x≤2. 
     
     
         13 . The cell of  claim 12 , wherein the cathode comprises an interlayer of the PrBa 0.5 Sr 0.5 Co 2−x Fe x O 5+δ  and an overlayer of the PrBa 0.5 Sr 0.5 Co 2−x Fe x O 5+δ  on the interlayer, wherein the overlayer has a higher porosity than the interlayer. 
     
     
         14 . A method of forming a bilayer cathode, the method comprising:
 forming an interlayer of a cathode material on a solid electrolyte; and   forming an overlayer of the cathode material on the interlayer, wherein the overlayer has a higher porosity than the interlayer.   
     
     
         15 . The method of  claim 14 , wherein forming the interlayer of the cathode materials comprises depositing a film of the cathode material via a vapor deposition process and forming the overlayer of the cathode material comprises depositing a layer of the cathode material via a solution phase deposition process. 
     
     
         16 . The method of  claim 14 , wherein the cathode material is a strontium cobalt perovskite. 
     
     
         17 . The method of  claim 16 , wherein the cathode material is PrBa 0.5 Sr 0.5 Co 2−x Fe x O 5+δ , where 0.4≤x≤2.