Hinterberg J, Zacherle T, De Souza RA. Activation volume tensor for oxygen-vacancy migration in strained CeO2 electrolytes.
PHYSICAL REVIEW LETTERS 2013;
110:205901. [PMID:
25167429 DOI:
10.1103/physrevlett.110.205901]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Indexed: 06/03/2023]
Abstract
We examine the effect of mechanical strain on the migration of oxygen vacancies in fluorite-structured ceria by means of density functional theory calculations. Different strain states (uniaxial, biaxial and isotropic) and strain magnitudes (up to ± 7%) are considered. From the calculations we extract the complete activation volume tensor for oxygen-vacancy migration in CeO(2), that is, all diagonal ΔV(mig,kk) and off-diagonal ΔV(mig,kl) tensor elements. These individual tensor elements are found, crucially, to be independent of strain state; they do, however, depend on stress (ΔV(mig,kk)) or effective pressure (ΔV(mig,kl)). Armed with knowledge of all tensor elements we predict strain states for which oxygen-ion transport in ceria is maximized. In general, with our approach the effect of an arbitrary strain state on the migration barrier for mass transport in a solid can be calculated quantitatively.
Collapse