Intrinsic layered defects in solid-state electrolyte Li0.33La0.56TiO3

Perovskite La2/3-xLi3xTiO3 is a typical solid-state electrolyte for all-solid-state lithium-ion batteries. The material system has been intensively studied because of its high bulk ionic conductivity and great efforts have been devoted to explore the structure-property relationship and further enhancement of the property through structural modification. However, the microstructure and its critical role in the ionic conductivity of La2/3-xLi3xTiO3 remain scarce in the literature. In this work, based on an in-depth study via aberration-corrected scanning transmission electron microscopy and first-principles calculation, we report the formation of intrinsic layered defects which act as Li-ion-blocking layers. By forming enclosed loops scaled from nanometers to micrometers, the layered defects are found to occur uniformly at domain boundaries. The results provide insights into the influence of these layered defects on Li-ion transport, as well as their formation mechanism as a result of phase transition at high sintering temperatures, paving the way to develop novel perovskite solid-state electrolytes via microstructure engineering. (C) 2021 Elsevier Ltd. All rights reserved.