Direct observation of A-site vacancies and domain boundary structures in polycrystalline Li0.34La0.51TiO3 solid-state electrolyte

Abstract

Atomic structure of the domain and the domain boundary in the polycrystalline electrolyte Li0.34La0.51TiO3 have been systematically studied via combined advanced scanning transmission electron microscopy methods. 90-degree-oriented and antiphase domain boundaries were both found in this Li-rich compound. Meanwhile, abundant La-vacancies were observed to be randomly created among the A-sites in the La-poor layer and were found to have resulted in the evident Ti-displacements towards the La-poor layer. Formation of such domain boundaries and the La-vacancy, associated with their microstructure features as well as their contributions to the material's ionic conductivity are discussed.