Probing the Phase Transition during the Formation of Lithium Lanthanum Zirconium Oxide Solid Electrolyte

Yubing Hu; Tianshi Feng; Lei Xu; Lifeng Zhang; Langli Luo

doi:10.1021/acsami.2c09660

Probing the Phase Transition during the Formation of Lithium Lanthanum Zirconium Oxide Solid Electrolyte

ACS Appl Mater Interfaces. 2022 Sep 21;14(37):41978-41987. doi: 10.1021/acsami.2c09660. Epub 2022 Sep 12.

Authors

Yubing Hu¹, Tianshi Feng¹, Lei Xu¹, Lifeng Zhang¹, Langli Luo^{1

2}

Affiliations

¹ Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China.
² Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, P. R. China.

PMID: 36094174
DOI: 10.1021/acsami.2c09660

Abstract

Lithium lanthanum zirconium oxide (LLZO) has long been considered as a promising solid electrolyte for all-solid-state lithium (Li) metal batteries because of its interfacial stability when coupled with a Li metal anode. However, the cubic phase of LLZO (c-LLZO) with a higher Li-ion conductivity has a complex atomic structure and is subject to complicated phase transition during its processing and working conditions, which remain largely elusive. Here, we reveal the phase transition process during the formation of c-LLZO nanotubes through detailed microscopic characterization by scanning and transmission electron microscopy as well as X-ray diffraction. We find four typical stages during the formation of c-LLZO along with several intermediate phases including lanthanum (La)-rich cubic lanthanum zirconium oxide (La-rich c-LZO), c-LZO, and La-rich c-LLZO. We also reveal the role of m-Li₂CO₃ and h-Li₂O₂ as the "phase mediator".

Keywords: LLZO; LZO; atomic scale; phase transition; transmission electron microscopy.