Predicting Oxygen Off-Stoichiometry and Hydrogen Incorporation in Complex Perovskite Oxides

Samantha Millican, Ann Deml, Meagan Papac, Andriy Zakutayev, Ryan O'Hayre, Aaron Holder, Charles Musgrave, Vladan Stevanovic

Research output: Contribution to journalArticlepeer-review

6 Scopus Citations

Abstract

Chemically and structurally complex solid compounds, including those with significant off-stoichiometry, are rapidly extending new material functionality across a variety of applications. Accelerated development of these compounds requires accurate predictions of material defect properties including effective defect formation energies and equilibrium defect concentrations. Traditional first-principles approaches typically examine dilute defect concentrations and relatively ordered atomic structures to identify the lowest energy defect sites. These approaches are rarely suitable for describing the disorder present in these systems and its influence on defect formation, which can lead to unphysically large predictions for defect concentrations. Here, we demonstrate a new method to accurately predict the temperature and pressure dependence of oxygen vacancy concentrations and proton interstitial concentrations in complex oxides. This method extends standard dilute defect calculations to incorporate atomic and magnetic disorder, employs the ensemble descriptions of defect sites resulting in improved predictions of defect formation energies, and accounts for effects beyond the dilute defect limit. To demonstrate our method, we show that the predicted defect concentrations in perovskites used as ceramic fuel cell cathodes, including Ba0.5Sr0.5Fe0.8Zn0.2O3-δ, Ba0.5Sr0.5Co0.8Fe0.2O3-δ, and BaCo1-x-y-zFexZryYzO3-δ, are in good agreement with experimental values, thereby opening the door for predictive design of complex oxides by these applications.

Original languageAmerican English
Pages (from-to)510-518
Number of pages9
JournalChemistry of Materials
Volume34
Issue number2
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-81454

Keywords

  • DFT
  • oxide
  • perovskite
  • vacancy

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