Unveiling Structure–Property Relationships in Sr ₂ Fe _1.5 Mo _0.5 O _6-δ , an Electrode Material for Symmetric Solid Oxide Fuel Cells

Journal Article · Fri Apr 06 00:00:00 EDT 2012 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja300831k· OSTI ID:1381054

Muñoz-García, Ana B. ^[1]; Bugaris, Daniel E. ^[2]; Pavone, Michele ^[1]; Hodges, Jason P. ^[3]; Huq, Ashfia ^[3]; Chen, Fanglin ^[4]; zur Loye, Hans-Conrad ^[2]; Carter, Emily A. ^[1]

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1. Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics, and Gerhard R. Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
2. Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
3. Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States

We characterize experimentally and theoretically the promising new solid oxide fuel cell electrode material Sr₂ Fe _1.5 Mo _0.5 O _6-δ (SFMO). Rietveld refinement of powder neutron diffraction data has determined that the crystal structure of this material is distorted from the ideal cubic simple perovskite, instead belonging to the orthorhombic space group Pnma. The refinement revealed the presence of oxygen vacancies in the as-synthesized material, resulting in a composition of Sr₂Fe_1.5Mo_0.5O_5.90(2) (δ = 0.10(2)). DFT+U theory predicts essentially the same concentration of oxygen vacancies. Theoretical analysis of the electronic structure allows us to elucidate the origin of this nonstoichiometry and the attendant mixed ion–electron conductor character so important for intermediate temperature fuel cell operation. The ease with which SFMO forms oxygen vacancies and allows for facile bulk oxide ion diffusivity is directly related to a strong hybridization of the Fe d and O p states, which is also responsible for its impressive electronic conductivity.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Heterogeneous Functional Materials Center (HeteroFoaM)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: SC0001061
• OSTI ID: 1381054
• Journal Information: Journal of the American Chemical Society, Vol. 134, Issue 15; Related Information: HeteroFoaM partners with University of South Carolina (lead); University of California, Santa Barbara; University of Connecticut; Georgia Institute of Technology; Princeton University; Rochester Institute of Technology; Savannah River National Laboratory; University of South Carolina; University of Utah; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
catalysis (heterogeneous)
energy storage (including batteries and capacitors)
hydrogen and fuel cells
mechanical behavior
charge transport
membrane
carbon sequestration
materials and chemistry by design
synthesis (novel materials)
synthesis (self-assembly)
synthesis (scalable processing)