Initiation of dendritic failure of LLZTO via sub-surface lithium deposition

Siniscalchi, M., Shi, Y., Li, G. , Gibson, J. S., Weatherup, R. S., Bonilla, R. S., Speller, S. C. and Grovenor, C. R. M. (2024) Initiation of dendritic failure of LLZTO via sub-surface lithium deposition. Energy and Environmental Science, (doi: 10.1039/D3EE03916A) (Early Online Publication)

Abstract

The occurrence of lithium deposition in occluded spaces within ceramic electrolytes due to electronic leakage currents can jeopardise the commercialization of power-dense solid-state batteries. Here, we utilize plasma-FIB serial sectioning to visualize the surface and sub-surface of a garnet solid electrolyte (LLZTO) after lithium plating. We study the morphology of surface spallation cracks, which represent the initial stage of dendrite formation. Employing a LiMg anode, we track the magnesium diffusion around these surface cracks with EDS. The absence of magnesium in early-stage cracks suggests they form due to the pressure build-up from the deposition of pure lithium in occluded pores near the electrolyte surface. These spallation cracks act as current focusing and stress concentration hot spots. Electron beam induced current imaging demonstrates that short-circuiting lithium dendrites grow from the spallations during plating. Thus, the sub-surface deposition of lithium is a possible explanation for the initiation of lithium dendrites in LLZTO.

• Item Type: Articles
• Additional Information: The authors acknowledge use of characterisation facilities within the David Cockayne Centre for Electron Microscopy, Department of Materials, University of Oxford, alongside capital equipment and financial support provided by the Henry Royce Institute (EP/R010145/1). M.S. acknowledges support from EPSRC PhD studentship EP/R513295/1. We are grateful to Jack Aspinall for providing the LiMg alloy. This work was supported by the Faraday Institution (grants FIRG020 and FIRG026).
• Status: Early Online Publication
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Li, Dr Guanchen
• Authors: Siniscalchi, M., Shi, Y., Li, G., Gibson, J. S., Weatherup, R. S., Bonilla, R. S., Speller, S. C., and Grovenor, C. R. M.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Energy and Environmental Science
• Publisher: Royal Society of Chemistry
• ISSN: 1754-5692
• ISSN (Online): 1754-5706
• Published Online: 14 February 2024
• Copyright Holders: Copyright © The Royal Society of Chemistry 2024
• First Published: First published in Energy and Environmental Science 2024
• Publisher Policy: Reproduced under a Creative Commons license