Interface Instability of Fe-Stabilized Li7La 3Zr2O12 versus Li Metal

Date Published
01/2018
Publication Type
Journal Article
Authors
DOI
10.1021/acs.jpcc.7b12387
Abstract

he interface stability versus Li represents a major challenge in the development of next-generation all-solid-state batteries (ASSB), which take advantage of the inherently safe ceramic electrolytes. Cubic Li7La3Zr2O12 garnets represent the most promising electrolytes for this technology. The high interfacial impedance versus Li is, however, still a bottleneck toward future devices. Herein, we studied the electrochemical performance of Fe3+-stabilized Li7La3Zr2O12 (LLZO:Fe) versus Li metal and found a very high total conductivity of 1.1 mS cm–1 at room temperature but a very high area specific resistance of ∼1 kΩ cm2. After removing the Li metal electrode we observe a black surface coloration at the interface, which clearly indicates interfacial degradation. Raman- and nanosecond laser-induced breakdown spectroscopy reveals, thereafter, the formation of a 130 μm thick tetragonal LLZO interlayer and a significant Li deficiency of about 1–2 formula units toward the interface. This shows that cubic LLZO:Fe is not stable versus Li metal by forming a thick tetragonal LLZO interlayer causing high interfacial impedance.

Journal
The Journal of Physical Chemistry C
Volume
122
Year of Publication
2018
Issue
7
Pagination
3780 - 3785
ISSN Number
1932-7447
Short Title
J. Phys. Chem. C
Refereed Designation
Refereed
Organizations
Download citation