Abstract
Despite their different chemistries, novel energy-storage systems, e.g., Li-air, Li-S, all-solid-state Li batteries, etc., face one critical challenge of forming a conductive and stable interface between Li metal and a solid electrolyte. An accurate understanding of the formation mechanism and the exact structure and chemistry of the rarely existing benign interfaces, such as the Li-cubic-Li7-3xAlxLa3Zr2O12 (c-LLZO) interface, is crucial for enabling the use of Li metal anodes. Due to spatial confinement and structural and chemical complications, current investigations are largely limited to theoretical calculations. Here, through an in situ formation of Li-c-LLZO interfaces inside an aberration-corrected scanning transmission electron microscope, we successfully reveal the interfacial chemical and structural progression. Upon contact with Li metal, the LLZO surface is reduced, which is accompanied by the simultaneous implantation of Li+, resulting in a tetragonal-like LLZO interphase that stabilizes at an extremely small thickness of around five unit cells. This interphase effectively prevented further interfacial reactions without compromising the ionic conductivity. Although the cubic-to-tetragonal transition is typically undesired during LLZO synthesis, the similar structural change was found to be the likely key to the observed benign interface. These insights provide a new perspective for designing Li-solid electrolyte interfaces that can enable the use of Li metal anodes in next-generation batteries.
Original language | English |
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Pages (from-to) | 7030-7036 |
Number of pages | 7 |
Journal | Nano Letters |
Volume | 16 |
Issue number | 11 |
DOIs | |
State | Published - Nov 9 2016 |
Funding
This research was sponsored by the U.S. Department of Energy (DOE), office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division. The microscopy work was conducted as a user project at the Center for Nanophase Materials Sciences (CNMS), which is sponsored at Oak Ridge National Laboratory (ORNL) by the Scientific User Facilities Division, BES-DOE. Materials synthesis (A. S. and J. S.) was supported by DOE - Energy Efficiency and Renewable Energy (DE-EE00006821). Ab initio calculations were performed with computing resources funded by the VirtuES project (ORNLLDRD 7739). J. L. acknowledges the support from NSF (CMMI-1436976) and NSSEFF (N00014-16-1-2569). K.Y. thanks the support from the NSF-China (11674052).
Funders | Funder number |
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BES-DOE | |
NSSEFF | N00014-16-1-2569 |
Scientific User Facilities Division | |
National Science Foundation | CMMI-1436976, 1436976 |
U.S. Department of Energy | |
Office of Energy Efficiency and Renewable Energy | ORNLLDRD 7739, DE-EE00006821 |
Basic Energy Sciences | |
Oak Ridge National Laboratory | |
Division of Materials Sciences and Engineering | |
National Natural Science Foundation of China | 11674052 |
Keywords
- Solid electrolytes
- electron microscopy
- in situ
- interface
- lithium metal
- passivation
- stability