Densification of ceria based electrolytes

Abstract

The fabrication of ceria based electrolytes to densities greater than 97% of the theoretical achievable density at temperatures below 1200° C., preferably approximately 1000° C., is disclosed. The electrolyte has a concentration of divalent cations minus an adjusted concentration of trivalent cations of between 0.01 mole % and 0.1 mole %.

1 . A half cell assembly comprising a substrate, an electrode and an electrolyte, wherein the electrolyte is a ceria based electrolyte with a density greater than 97% of the theoretical achievable density and with a concentration of divalent cations minus an adjusted concentration of trivalent cations of between 0.01 mole % and 0.1 mole % inclusive. 
     
     
         2 . A half cell assembly as defined in  claim 1 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.02 mole % and 0.09 mole % inclusive. 
     
     
         3 . A half cell assembly as defined in  claim 1 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.03 mole % and 0.08 mole % inclusive. 
     
     
         4 . A half cell assembly as defined in  claim 1 , wherein the concentration of trivalent cations is adjusted by multiplication by a number between 5 and 10. 
     
     
         5 . A half cell assembly as defined in  claim 1 , wherein the electrolyte is sintered. 
     
     
         6 . A fuel cell assembly comprising:
 a half cell assembly comprising a substrate, a first electrode and an electrolyte, wherein the electrolyte is a ceria based electrolyte with a density greater than 97% of the theoretical achievable density and with a concentration of divalent cations minus an adjusted concentration of trivalent cations of between 0.01 mole % and 0.1 mole % inclusive; and   a second electrode provided on the opposite side of the electrolyte from the first electrode.   
     
     
         7 . A fuel cell assembly as defined in  claim 6 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.02 mole % and 0.09 mole % inclusive. 
     
     
         8 . A fuel cell assembly as defined in  claim 7 , wherein the first electrode is an anode and the second electrode is a cathode. 
     
     
         9 . A fuel cell assembly as defined in  claim 6 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.03 mole % and 0.08 mole % inclusive. 
     
     
         10 . A fuel cell as defined in  claim 9 , wherein the first electrode is an anode and the second electrode is a cathode. 
     
     
         11 . A fuel cell assembly as defined in  claim 6 , wherein the concentration of trivalent cations is adjusted by multiplication by a number between 5 and 10. 
     
     
         12 . A fuel cell as defined in  claim 11 , wherein the first electrode is an anode and the second electrode is a cathode. 
     
     
         13 . A fuel cell assembly as defined in  claim 6 , wherein the electrolyte is sintered. 
     
     
         14 . A fuel cell as defined in  claim 13 , wherein the first electrode is an anode and the second electrode is a cathode. 
     
     
         15 . A fuel cell assembly as defined in  claim 6 , wherein the first electrode is an anode and the second electrode is a cathode. 
     
     
         16 . An oxygen generator, comprising:
 a half cell assembly comprising a substrate, a first electrode and an electrolyte, wherein the electrolyte is a ceria based electrolyte with a density greater than 97% of the theoretical achievable density and with a concentration of divalent cations minus an adjusted concentration of trivalent cations of between 0.01 mole % and 0.1 mole % inclusive; and   a second electrode provided on the opposite side of the electrolyte from the first electrode.   
     
     
         17 . An oxygen generator as defined in  claim 16 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.02 mole % and 0.09 mole % inclusive. 
     
     
         18 . An oxygen generator as defined in  claim 16 , wherein the concentration of divalent cations minus an adjusted concentration of trivalent cations is between 0.03 mole % and 0.08 mole % inclusive. 
     
     
         19 . An oxygen generator as defined in  claim 16 , wherein the concentration of trivalent cations is adjusted by multiplication by a number between 5 and 10. 
     
     
         20 . An oxygen generator as defined in  claim 16 , wherein the electrolyte is sintered.