Factors controlling oxygen migration barriers in perovskites

• Published in: Solid state ionics Vol. 296; no. C; pp. 71 - 77
• Main Authors: Mayeshiba, Tam T., Morgan, Dane D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2016; Elsevier
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2016.09.007

Perovskites with fast oxygen ion conduction can enable technologies like solid oxide fuel cells. One component of fast oxygen ion conduction is low oxygen migration barrier. Here we apply ab initio methods on over 40 perovskites to produce a database of oxygen migration barriers ranging from 0.2 to 1.6eV. Mining the database revealed that systems with low barriers also have low metal-oxygen bond strength, as measured by oxygen vacancy formation energy and oxygen p-band center energy. These correlations provide a powerful descriptor for the development of new oxygen ion conductors and may explain the poor stability of some of the best oxygen conducting perovskites under reducing conditions. Other commonly-cited measures of space, volume, or structure ideality showed only weak correlation with migration barrier. The lowest migration barriers (<0.5eV) belong to perovskites with non-transition-metal B-site cations, and may require vacancy-creation strategies that involve no dopants or low-association dopants for optimal performance. •Calculated oxygen migration barriers in 40+ perovskites range from 0.2 to 1.6eV.•The lowest migration barriers are for non-transition-metal B-site cations.•Barriers correlate well with M-O bond strength descriptors for this database.•Barriers do not correlate with many other proposed descriptors for this database.