عنوان

Designing Optimal Perovskite Structure for High Ionic Conduction.

Number

LA5491t4j6

Title Proper

Designing Optimal Perovskite Structure for High Ionic Conduction.

General Material Designation

[Article]

First Statement of Responsibility

Gao, RanJain, Abhinav CPPandya, ShishirDong, YongqiYuan, YakunZhou, HuaDedon, Liv RThoréton, VincentSaremi, SaharXu, RuijuanLuo, AileenChen, TingGopalan, VenkatramanErtekin, ElifKilner, JohnIshihara, TatsumiPerry, Nicola HTrinkle, Dallas RMartin, Lane W

Text of Note

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.

Date of Publication

2020

Title

Lawrence Berkeley National Laboratory

Electronic name

[Article]

276379

a

Y