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

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

TitleInterface Instability of Fe-Stabilized Li7La 3Zr2O12 versus Li Metal
Publication TypeJournal Article
Year of Publication2018
AuthorsDaniel Rettenwander, Reinhard Wagner, Andreas Reyer, Maximilian Bonta, Lei Cheng, Marca M Doeff, Andreas Limbeck, Martin Wilkening, Georg Amthauer
JournalThe Journal of Physical Chemistry C
Volume122
Issue7
Pagination3780 - 3785
Date Published01/2018
ISSN1932-7447
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.

DOI10.1021/acs.jpcc.7b12387
Short TitleJ. Phys. Chem. C
Refereed DesignationRefereed