- Main
Designing Optimal Perovskite Structure for High Ionic Conduction.
- Author(s): Gao, Ran
- Jain, Abhinav CP
- Pandya, Shishir
- Dong, Yongqi
- Yuan, Yakun
- Zhou, Hua
- Dedon, Liv R
- Thoréton, Vincent
- Saremi, Sahar
- Xu, Ruijuan
- Luo, Aileen
- Chen, Ting
- Gopalan, Venkatraman
- Ertekin, Elif
- Kilner, John
- Ishihara, Tatsumi
- Perry, Nicola H
- Trinkle, Dallas R
- Martin, Lane W
- et al.
Published Web Location
https://doi.org/10.1002/adma.201905178Abstract
Solid-oxide fuel/electrolyzer cells are limited by a dearth of electrolyte materials with low ohmic loss and an incomplete understanding of the structure-property relationships that would enable the rational design of better materials. Here, using epitaxial thin-film growth, synchrotron radiation, impedance spectroscopy, and density-functional theory, the impact of structural parameters (i.e., unit-cell volume and octahedral rotations) on ionic conductivity is delineated in La0.9 Sr0.1 Ga0.95 Mg0.05 O3- δ . As compared to the zero-strain state, compressive strain reduces the unit-cell volume while maintaining large octahedral rotations, resulting in a strong reduction of ionic conductivity, while tensile strain increases the unit-cell volume while quenching octahedral rotations, resulting in a negligible effect on the ionic conductivity. Calculations reveal that larger unit-cell volumes and octahedral rotations decrease migration barriers and create low-energy migration pathways, respectively. The desired combination of large unit-cell volume and octahedral rotations is normally contraindicated, but through the creation of superlattice structures both expanded unit-cell volume and large octahedral rotations are experimentally realized, which result in an enhancement of the ionic conductivity. All told, the potential to tune ionic conductivity with structure alone by a factor of ≈2.5 at around 600 °C is observed, which sheds new light on the rational design of ion-conducting perovskite electrolytes.