| Abstract
| - Atomic-scale studies using advanced simulation techniques have investigated the energetics of defects, oxygen migration, and dopant incorporation in the proton-conducting SrCeO3 system. Favorable dopant-proton association is predicted, in accordance with reported proton-trapping effects.
- Atomic-scale studies using advanced simulation techniques have investigated the energetics of defects,oxygen migration, and dopant incorporation in the proton-conducting SrCeO3 system. The interatomicpotential model first reproduces the observed distorted perovskite structure of SrCeO3. Substitution withtrivalent dopants (M) on the A site in SrCe(Yb)O3-δ (via Vo•• consumption) is compared with substitution on the B site (via Vo•• creation); the results support the premise that the absence of ionic conductivity at low doping levels is associated with dopant partitioning over both A and B sites. Dopant-vacancy association is predicted to occur in SrCe0.9M0.1O2.95 for a wide range of M cations. Formation of(M‘Ce−OHo•) clusters is also calculated to be favorable in accordance with reported proton-trapping effects.The lowest M‘Ce−OHo• binding energies and the largest M−H distances are found for the most commondopants for proton conductivity in the SrCeO3 system, namely, Y and Yb. The pathway for oxygenmigration is proposed as a curved trajectory with an asymmetric energy distribution. The lowest energyredox process is calculated to be oxidation with the formation of holes in accordance with the observationof p-type conductivity at increasing oxygen partial pressures (pO2).
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