Phase stable doped zirconia electrolyte compositions with low degradation

Patent metadata

Field	Value
Publication number	US-9799909-B2
Application number	US-201615205852-A
Country	US
Kind code	B2
Filing date	Jul 8, 2016
Priority date	Jan 26, 2010
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A solid oxide fuel cell (SOFC) includes a cathode electrode, a solid oxide electrolyte, and an anode electrode. The electrolyte and/or electrode composition includes zirconia stabilized with (i) scandia, (ii) ceria, and (iii) at least one of yttria and ytterbia. The composition does not experience a degradation of ionic conductivity of greater than 15% after 4000 hrs at a temperature of 850° C.

First claim

The invention claimed is:

1. A method of operating a solid oxide fuel cell comprising a cubic phase zirconia electrolyte stabilized with scandia and ceria, the method comprising operating the solid oxide fuel cell for at least 4000 hrs such that an electrolyte of the fuel cell does not experience a degradation of ionic conductivity of greater than 15%,
wherein the zirconia electrolyte stabilized with scandia and ceria has a formula (ZrO 2 ) 1-w-x-b (Sc 2 O 3 ) w (CeO 2 ) x (Yb 2 O 3 ) b , where 0.09≦w≦0.11; 0.005≦x≦0.015 and 0.0025≦b≦0.015.

2. The method of claim 1 , wherein the electrolyte comprises scandia, ceria and ytterbia stabilized zirconia comprising the cubic phase which substantially lacks tetragonal phase domains after operating in the solid oxide fuel cell at 850° C. for at least 4000 hours in at least one of air or hydrogen ambient.

3. The method of claim 1 , wherein:
0.01≦x≦0.015 and 0.005≦b≦0.0125.

4. The method of claim 3 , wherein:
0.005≦b≦0.01.

5. The method of claim 4 , wherein:
w=0.1, b=0.01 and x=0.01.

6. The method of claim 1 , wherein:
0.005≦x≦0.0125 and 0.0025≦b≦0.01.

7. The method of claim 1 , wherein: 0.0025≦b≦0.0125.

8. The method of claim 7 , wherein:
0.005≦x≦0.01 and 0.005≦b≦0.01.

9. The method of claim 4 , wherein:
w=0.1 and x=0.01.

10. The method of claim 2 , wherein:
the composition does not experience a cubic to rhombohedral phase transition at a temperature of about 25 to 850° C.

Assignees

• Bloom Energy Corp

Inventors

• Armstrong Tad
• El Batawi Emad
• Janousek Martin
• Pillai Manoj

Classifications

• Y02E60/50

  Fuel cells · CPC title

• C04B35/486

  Fine ceramics · CPC title

• C01G25/006

  Compounds containing zirconium, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• Y02E60/521

  Cross-Sectional Technologies · mapped topic