Investigating the dendritic growth during full cell cycling of garnet electrolyte in direct contact with Li metal.
File(s)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
All-solid-state batteries including a garnet ceramic as electrolyte are potential candidates to replace the currently used Li-ion technology, as they offer safer operation and higher energy storage performances. However, the development of ceramic electrolyte batteries faces several challenges at the electrode/electrolyte interfaces, which need to withstand high current densities to enable competing C-rates. In this work, we investigate the limits of the anode/electrolyte interface in a full cell that includes a Li-metal anode, LiFePO4 cathode, and garnet ceramic electrolyte. The addition of a liquid interfacial layer between the cathode and the ceramic electrolyte is found to be a prerequisite to achieve low interfacial resistance and to enable full use of the active material contained in the porous electrode. Reproducible and constant discharge capacities are extracted from the cathode active material during the first 20 cycles, revealing high efficiency of the garnet as electrolyte and the interfaces, but prolonged cycling leads to abrupt cell failure. By using a combination of structural and chemical characterization techniques, such as SEM and solid-state NMR, as well as electrochemical and impedance spectroscopy, it is demonstrated that a sudden impedance drop occurs in the cell due to the formation of metallic Li and its propagation within the ceramic electrolyte. This degradation process is originated at the interface between the Li-metal anode and the ceramic electrolyte layer and leads to electromechanical failure and cell short-circuit. Improvement of the performances is observed when cycling the full cell at 55 °C, as the Li-metal softening favors the interfacial contact. Various degradation mechanisms are proposed to explain this behavior.
Date Issued
2017-01-05
Date Acceptance
2017-01-05
Citation
ACS Applied Materials and Interfaces, 2017, 9 (4), pp.3808-3816
ISSN
1944-8244
Publisher
American Chemical Society
Start Page
3808
End Page
3816
Journal / Book Title
ACS Applied Materials and Interfaces
Volume
9
Issue
4
Copyright Statement
© 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces after peer review and technical editing by the publisher. To access the final edited and published work see https://dx.doi.org/10.1021/acsami.6b13925
Identifier
http://www.ncbi.nlm.nih.gov/pubmed/28055178
Subjects
Li-metal/garnet interface
all-solid-state batteries
degradation mechanisms
dendritic lithium formation
full cell cycling
garnet electrolyte
post mortem analysis
Nanoscience & Nanotechnology
0904 Chemical Engineering
0303 Macromolecular And Materials Chemistry
0306 Physical Chemistry (Incl. Structural)
Publication Status
Published
Coverage Spatial
United States