Oxygen Migration Pathways in Layered LnBaCo2O6-δ (Ln = La – Y) Perovskites

Fabian Hesse, Ivan da Silva, Jan-Willem G. Bos

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Abstract

Layered LnBaCo2O6-δ perovskites are important mixed ionic-electronic conductors, exhibiting outstanding catalytic properties for the oxygen evolution/reduction reaction. These phases exhibit considerable structural complexity, in particular, near room temperature, where a number of oxygen vacancy ordered superstructures are found. This study uses bond valence site energy calculations to demonstrate the key underlying structural features that favor facile ionic migration. BVSE calculations show that the 1D vacancy ordering for Ln = Sm–Tb could be beneficial at low temperatures as new pathways with reduced barriers emerge. By contrast, the 2D vacancy ordering for Ln = Dy and Y is not beneficial for ionic transport with the basic layered parent material having lower migration barriers. Overall, the key criterion for low migration barriers is an expanded ab plane, supported by Ba, coupled to a small Ln size. Hence, Ln = Y should be the best composition, but this is stymied by the low temperature 2D vacancy ordering and moderate temperature stability. The evolution of the oxygen cycling capability of these materials is also reported.
Original languageEnglish
Pages (from-to)1538-1549
Number of pages12
JournalJACS Au
Volume4
Issue number4
Early online date2 Apr 2024
DOIs
Publication statusPublished - 22 Apr 2024

Keywords

  • BVSE calculations
  • cobalt oxide perovskites
  • layered double perovskite
  • mixed ionic electronic conductor
  • neutron powder diffraction
  • oxygen vacancy ordering

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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