Issue 12, 2022

Lithium deposition mechanism on Si and Cu substrates in the carbonate electrolyte

Abstract

Electrochemical Li deposition occurs in fast-charging Li-ion batteries and Li metal batteries. The morphologies of the Li deposits govern the reversibility of the deposition/stripping reaction, and affect the tendency of internal-shorting, therefore determining the performance and safety of Li-ion and Li metal batteries. Many different morphologies, including hemi-sphere, granular, columnar, whisker, and dendrite, have been observed. However, how Li deposits grow into different morphologies largely remains elusive. In this work, we reveal the mechanism of Li growth on Si and Cu substrates in a commercial carbonate electrolyte by combing electron imaging, optical imaging, molecular dynamics simulation and electrochemical tests with theoretical analysis. Li growth dynamics is analyzed by comparing images of Li deposits at different currents, capacities, and temperatures. For Si substrates, a 3D-2D growth mechanism is found almost irrespective of the current density. For Cu substrates, the growth follows a 3D-2D mechanism under quasi-equilibrium conditions but transitions to a different mechanism under high current density, in which a 1D Li whisker grows out from Li islands. The tendency of whisker growth on both substrates is quantified and its dependence on current density is determined. It is revealed that all Li deposits on Cu become whiskers beyond a critical current density (Jw = 0.79 ± 0.10 mA cm−2) while Si substrates have a much larger Jw (>10 mA cm−2), leading to virtually no whisker formation. In addition, correlations between whisker growth, coulombic efficiency, and the tendency of internal shorting are determined. The nucleation and growth mechanism, as well as the transition between morphologies, are comprehensively discussed based on the results of this work and state-of-the-art findings on Li deposition.

Graphical abstract: Lithium deposition mechanism on Si and Cu substrates in the carbonate electrolyte

Supplementary files

Article information

Article type
Paper
Submitted
09 6 2022
Accepted
10 10 2022
First published
26 10 2022

Energy Environ. Sci., 2022,15, 5284-5299

Lithium deposition mechanism on Si and Cu substrates in the carbonate electrolyte

J. Sun, J. Peng, T. Ring, L. Whittaker-Brooks, J. Zhu, D. Fraggedakis, J. Niu, T. Gao and F. Wang, Energy Environ. Sci., 2022, 15, 5284 DOI: 10.1039/D2EE01833K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements