Defect chemistry and oxygen non-stoichiometry in SrFe0.2Co0.4Mo0.4O3-δ ceramic oxide for solid oxide fuel cells

SrFe 0.2 Co 0.4 Mo 0.4 O 3-δ (SFCM) is a ceramic oxide that has the potential to replace conventional Ni-based cermet anodes and is appropriate for use in solid oxide fuel cells operating at low temperatures (below 650 ° C). SFCM was shown to be phase stable with n-type conductivity above 43 S/cm un...

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Bibliographic Details
Published in:Ionics 2020-11, Vol.26 (11), p.5641-5649
Main Authors: Stanley, Patrick, Hussain, A. Mohammed, Huang, Yi-Lin, Gritton, J. Evans, Wachsman, Eric D.
Format: Article
Language:English
Subjects:
Cermets
Chemistry
Chemistry and Materials Science
Condensed Matter Physics
Electrochemistry
Energy Storage
Enthalpy
Low temperature
Optical and Electronic Materials
Original Paper
Oxidation
Oxygen
Physics
Renewable and Green Energy
Solid oxide fuel cells
Stoichiometry
Vacancies
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Summary:SrFe 0.2 Co 0.4 Mo 0.4 O 3-δ (SFCM) is a ceramic oxide that has the potential to replace conventional Ni-based cermet anodes and is appropriate for use in solid oxide fuel cells operating at low temperatures (below 650 ° C). SFCM was shown to be phase stable with n-type conductivity above 43 S/cm under reducing conditions and reversibly creates secondary phases under oxidizing conditions with p-type conductivity around 4 S/cm at 600 ° C. SFCM begins desorbing oxygen and creating vacancies under nitrogen at 350 ° C and continues to do so above 800 ° C. Under oxidizing conditions, SFCM remains near stoichiometric, with oxygen non-stoichiometry changes below δ = 0.003. Once exposed to reducing conditions, SFCM can obtain a non-stoichiometry up to δ = 0.176 due to the reduction of the three multivalent B-site cations resulting in a low enthalpy of formation for oxygen vacancies at 109 kJ mol − 1 . This data is used to propose a low pO 2 defect equilibrium model and diagram to explain the oxygen vacancy generation behavior under reducing conditions across temperatures.
ISSN:0947-7047
1862-0760
DOI:10.1007/s11581-020-03674-7