DFT investigation on SmCoO3-based mixed ionic-electronic conductor

Atomistic simulation techniques are used to examine the perovskite-structured SmCoO3, a material whose electrochemical properties make it attractive for use in heterogeneous oxidation catalysis, in gas sensors and in solid oxide fuel cells. The electronic structure, oxygen vacancy at different charge state, and oxygen diffusion process in cubic SmCoO3 are investigated. The 100% polarization of conduction carriers in Sm4f majority spin channel could introduce spin-polarized charge carriers into SmCoO3 efficiently. The formation energies of oxygen vacancies are positive under investigated chemical potentials and are nearly identical at charge state from 0 to +2. The ionization of VO0 to VO2+ does not show evident changes in the atomistic displacements of ions surrounding the vacancy. Moderate energy barrier (0.81 eV) of oxygen migration in lattice suggests high oxygen mobility of compound. The calculations show that steric factors, lattice relaxation, and oxygen polarization play the major roles for oxygen conduction in SmCoO3.

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