Unveiling structure-property relationships in Sr 2Fe 1.5Mo 0.5O 6-δ, an electrode material for symmetric solid oxide fuel cells

Ana B. Muñoz-García, Daniel E. Bugaris, Michele Pavone, Jason P. Hodges, Ashfia Huq, Fanglin Chen, Hans Conrad Zur Loye, Emily A. Carter

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

We characterize experimentally and theoretically the promising new solid oxide fuel cell electrode material Sr 2Fe 1.5Mo 0.5O 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 Sr 2Fe 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.

Original languageEnglish (US)
Pages (from-to)6826-6833
Number of pages8
JournalJournal of the American Chemical Society
Volume134
Issue number15
DOIs
StatePublished - Apr 18 2012

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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