Regulation of Dendrite-Free Li Plating Via Lithiophilic Sites on Lithium-Alloy Surface

Abstract

Lithium (Li) deposition behavior plays an important role in dendrite formation and the subsequent performance of lithium metal batteries. This work reveals the impact of the lithiophilic sites of lithium-alloy on the Li plating process via the first-principles calculations. We find that the Li deposition mechanisms on the Li metal and Li22Sn5 surface are different due to the lithiophilic sites. We first propose that Li plating on the Li metal surface goes through the "adsorption-reduction-desorption-heterogeneous nucleation-cluster drop"process, while it undergoes the "adsorption-reduction-growth"process on the Li22Sn5 surface. The lower adsorption energy contributes to the easy adsorption of Li on the lithiophilic sites of the Li22Sn5 surface. The lower Li reduction energy on the Li metal surface indicates that it is easy for Li to be reduced on the Li metal surface, attributed to its higher Fermi energy level. Furthermore, the faster Li diffusion on the Li22Sn5 surface results in smooth Li deposition, which is based on a "two-Li synergy diffusion"mechanism. However, Li diffuses more slowly on the Li metal surface than on the Li22Sn5 surface due to the "single Li diffusion"mechanism. This work provides a fundamental understanding on the impact of lithiophilic sites of Li alloy on the Li plating process and points out that the future design of 3D Li-alloy substrates decorated with multilithiophilic sites can prevent dendrite formation on the lithium-alloy substrate by guiding uniform Li deposition.

Department(s)

Mechanical and Aerospace Engineering

Comments

his work was supported by the National Natural Science Foundation of China (no. U21A20170), the Ministry of Science and Technology of China (no. 2019YFA0705703), and China Postdoctoral Science Foundation [no. 2021M701873 (B.Z.), 2022M711791 (Y.H.)].

Keywords and Phrases

Adsorption Energy; Li Diffusion; Lithiophilic Sites; Reduction Energy; the First-Principles

International Standard Serial Number (ISSN)

1944-8252; 1944-8244

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2022 American Chemical Society, All rights reserved.

Publication Date

01 Jan 2022

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