A glance at the influence of different dopant elements on Li7La3Zr2O12 garnets

Official URL: https://dx.doi.org/10.1007/s11581-021-04152-4

Lithium lanthanum zirconates (LLZOs) are a family of solid electrolytes that have been increasingly under development since 2007. The high-temperature cubic LLZO has been the focus of the study due to its excellent ionic conductivity, higher stability against electrodes, and ease of fabrication in comparison to other solid electrolytes. Many advancements have been achieved in this area; however, still, there is room for further improvements. Recent findings have suggested the idea of using supervalent dopants such as (Ba2+, Sr2+, Eu2+, Al3+, Ga3+, Gd3+, Fe3+ Sc3+, Sm3+, Y3+, Eu3+, Ge4+, Ce4+, Sb5+ Ta5+, Nb5+, and W6+) to tailor the properties of LLZOs and therefore, make them applicable in different areas such as all-solid-state batteries, solid oxide fuel cells, and electrochemical sensors. Many results concerning the structure and consequently, the site preference of compositional ions (Li+, La3+, and Zr4+) of LLZO electrolytes have been published in recent years, but the diversity is such high that might confuse the reader when choosing the right topic of study. Therefore, in this review, we are aiming to summarize, categorize, and clarify recent advances in cubic LLZO solid electrolytes. A further aim of this review is to give a more in-depth insight into the structure and, therefore, the origin of the ionic conductivity in cubic LLZO.