Solid-state lithium batteries will revolutionize the lithium-ion battery and energy storage applications if certain key challenges can be resolved. The formation of lithium-protrusions (dendrites) that can cause catastrophic short-circuiting is one of the main obstacles, and progresses by a mechanism that is not yet fully understood. By utilizing X-ray computed tomography with nanoscale resolution, the 3D morphology of lithium protrusions inside short-circuited solid electrolytes has been obtained for the first time. Distinguishable from adjacent voids, lithium protrusions partially filled cracks that tended to propagate intergranularly through the solid electrolyte, forming a large waved plane in the shape of the grain boundaries. Occasionally, the lithium protrusions bifurcate into flat planes in a transgranular mode. Within the cracks themselves, lithium protrusions are preferentially located in regions of relatively low curvature. The crack volume filled with lithium in two samples is 82.0% and 83.1%, even though they have distinctly different relative densities. Pre-existing pores in the solid electrolyte, as a consequence of fabrication, can also be part-filled with lithium, but do not have a significant influence on the crack path. The crack/lithium-protrusion behavior qualitatively supports a model of propagation combining electrochemical and mechanical effects.
Bibliographical noteFunding Information:
The authors acknowledge the financial support from the Faraday Institution All‐Solid‐State Batteries with Li Anode (EP/S003053/1, FIRG007) and the EPSRC (EP/P009050/1); P.R.S. acknowledges the support of The Royal Academy of Engineering (CIET178/59). FIB‐SEM experiments were carried out at the Research Complex at Harwell, UK.
© 2020 Wiley-VCH GmbH
Copyright 2021 Elsevier B.V., All rights reserved.
- lithium protrusions
- solid-state batteries
- X-ray computed tomography
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics