Garnet Electrolyte Surface Degradation and Recovery

Garnet Electrolyte Surface Degradation and Recovery

TitleGarnet Electrolyte Surface Degradation and Recovery
Publication TypeJournal Article
Year of Publication2018
AuthorsLei Cheng, Miao Liu, Apurva Mehta, Huolin L Xin, Feng Lin, Kristin A Persson, Guoying Chen, Ethan J Crumlin, Marca M Doeff
JournalACS Applied Energy Materials
Volume1
Issue12
Pagination7244 - 7252
Date Published11/2018
ISSN2574-0962
Abstract

Ceramic materials based on the garnet structure Li7La3Zr2O12 (LLZO) show great promise as lithium-ion conducting electrolytes for solid-state lithium batteries. However, these materials exhibit surface degradation when exposed to air and moisture, which adversely impacts their functioning in operating devices. In this work, we use several depth-profiling and in situ techniques to probe the nature of the surface reactions that occur when aluminum (Al)-substituted LLZO is exposed to air. These experiments show that a proton exchange reaction occurs near the surface of the LLZO and leads to change in its chemistry and structure, concomitant with the formation of Li2CO3. But these reactions can be readily reversed by heating samples at 250 °C under an inert atmosphere to recover LLZO surface chemistry and structure. Symmetrical cells containing samples treated this way exhibited much lower area specific impedances than those containing air-exposed LLZO without the treatment, confirming the reversal of the degradation process. Our results show a process to rejuvenate LLZO surface, and this opens the possibility of integrating this material in solid-state devices.

DOI10.1021/acsaem.8b01723
Short TitleACS Appl. Energy Mater.
Refereed DesignationRefereed