SOFC cathode compositions with improved resistance to SOFC degradation

Patent metadata

Field	Value
Publication number	US-10249883-B2
Application number	US-201514936250-A
Country	US
Kind code	B2
Filing date	Nov 9, 2015
Priority date	Nov 12, 2014
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A solid oxide fuel cell (SOFC) includes a solid oxide electrolyte with a zirconia-based ceramic, an anode electrode, and a cathode electrode that includes a ceria-based ceramic component and an electrically conductive component. Another SOFC includes a solid oxide electrolyte containing a zirconia-based ceramic, an anode electrode, and a cathode electrode that includes an electrically conductive component and an ionically conductive component, in which the ionically conductive component includes a zirconia-based ceramic containing scandia and at least one of ceria, ytterbia and yttria.

First claim

The invention claimed is:

1. A solid oxide fuel cell (SOFC), comprising:
a solid oxide electrolyte comprising a zirconia-based ceramic;
an anode electrode; and
a cathode electrode comprising an electrically conductive component and an ionically conductive component, wherein the ionically conductive component comprises a zirconia-based ceramic containing scandia, 0.25-1.25 mol % ceria, and 0.25-1.25 mol % ytterbia, yttria, or a combination of ytterbia and yttria.

2. The SOFC of claim 1 , wherein the cathode electrode contains 10-90 wt % of each of the ionically conductive component and 10-90 wt % of the electrically conductive component.

3. The SOFC of claim 1 , wherein the solid oxide electrolyte comprises scandia stabilized zirconia.

4. The SOFC of claim 1 , wherein the solid oxide electrolyte comprises a formula (ZrO 2 ) 1-w-x-z (Sc 2 O 3 ) w (CeO 2 ) x (Y 2 O 3 ) a (Yb 2 O 3 ) b , wherein 0.09≤w≤0.11, 0 <x≤0.0125, a+b=z, and 0.0025≤z≤0.0125.

5. The SOFC of claim 4 , wherein 0.009<x≤0.011, 0.009≤z≤0.011, and wherein the ionically conductive component and the solid oxide electrolyte have the same composition.

6. The SOFC of claim 1 , wherein the electrically conductive component comprises an electrically conductive ceramic selected from the group consisting of lanthanum strontium manganite (LSM), lanthanum calcium manganite (LCM), lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium ferrite (LSF), lanthanum strontium manganese ferrite (LSMF) and lanthanum strontium chromite (LSCr), and lanthanum strontium cobaltite (LSCo).

7. The SOFC of claim 1 , wherein the cathode electrode further comprises 0.5 wt % or less of at least one of an additional catalyst material comprising one or more of cobalt, platinum, or ruthenium, and a sintering aid comprising one or more of cobalt, magnesium, nickel, iron, or copper.

8. The SOFC of claim 1 , the cathode electrode has a graded composition where a ratio of the ionically conductive component to electrically conductive component in the cathode electrode decreases from an electrolyte-cathode interface towards a free surface of the cathode electrode.

9. A method of operating a solid oxide fuel cell comprising a zirconia-based electrolyte and a cathode electrode containing an electrically conductive component and an ionically conductive component, the method comprising:
operating the solid oxide fuel cell at 800-850° C. for at least 4000 hrs such that the SOFC does not experience a voltage degradation of greater than 15%,
wherein the ionically conductive component comprises a zirconia-based ceramic containing scandia, 0.25-1.25 mol % ceria, and 0.25-1.25 mol % ytterbia, yttria, or a combination of ytterbia and yttria.

10. The method of claim 9 , wherein the electrically conductive component comprises a perovskite ceramic.

Assignees

• Bloom Energy Corp

Inventors

• Leming Andres
• El Batawi Emad
• Gasda Michael
• Armstrong Tad
• Wilson James

Classifications

• H01M4/92

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• H01M4/9066

  of metal-ceramic composites or mixtures, e.g. cermets · CPC title

• H01M2004/8689

  Positive electrodes · CPC title

• H01M4/9033 Primary

  Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title