Phase stable doped zirconia electrolyte compositions with low degradation

• US 8,580,456 B2
• Filed: 01/19/2011
• Issued: 11/12/2013
• Est. Priority Date: 01/26/2010
• Status: Active Grant

• Current Assignee: Bloom Energy Corporation
• Original Assignee: Bloom Energy Corporation
• Inventors: Armstrong, Tad, Batawi, Emad El, Janousek, Martin, Pillai, Manoj
• Primary Examiner(s): Cano, Milton I
• Assistant Examiner(s): THOMAS, BRENT C
• Application Number:
  US13/009,085
• Publication Number:
  US 20110183233A1
• Time in Patent Office: 1,028 Days
• Field of Search: 429/496, 429/482
• US Class Current: 429/496
• CPC Class Codes: C01G 25/006 Compounds containing, besides zirconium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 25/02 Oxides
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3246 Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia
• CPC Class Codes: C04B 2235/762 Cubic symmetry, e.g. beta-SiC
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/486 Fine ceramics
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 8/1246 the electrolyte consisting of oxides
• CPC Class Codes: H01M 8/1253 the electrolyte containing zirconium oxide
• CPC Class Codes: H01M 8/126 the electrolyte containing cerium oxide
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

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.

Claims

1. A scandia stabilized zirconia electrolyte composition for a solid oxide fuel cell, comprising a formula (ZrO₂)_1-w-x-a-b(Sc₂O₃)_w(CeO₂)_x(Y₂O₃)_a(Yb₂O₃)_b, where 0.09≦

w≦

0.11;

0<

x≦

0.025;

a+b=z;

0≦

z≦

0.025; and

x+z≧

0.02, wherein;

w=0.1;

x=0.01; and

z=0.01; and

the composition comprises zirconia containing 10 mol % Sc₂O₃, 1 mol % CeO₂ and 1 mol % Y₂O₃.

2. The electrolyte composition of claim 1, wherein:

the composition does not experience a degradation of ionic conductivity of greater than 15% after 4000 hrs and at a temperature of 850°

C.;

the composition comprises a cubic phase which substantially lacks tetragonal phase domains after operating in a solid oxide fuel cell at 850°

C. for at least 4000 hours in at least one of air or hydrogen ambient; and

the composition does not experience a cubic to rhombohedral phase transition at a temperature of about 25 to 850°

C.

3. The composition of claim 1, wherein the composition is utilized as an electrolyte layer of a planar solid oxide fuel cell comprising an anode and a cathode, and the electrolyte layer supports the anode and cathode.