Improving Interface Stability of Si Anodes by Mg Coating in Li-Ion Batteries

Zhifei Li, Caleb Stetson, Glenn Teeter, Andrew Norman, Yeyoung Ha, Bertrand Tremolet de Villers, Zoey Huey, Patrick Walker, Sang-Don Han, Steven DeCaluwe, Chun-Sheng Jiang, Anthony Burrell, Andriy Zakutayev

Research output: Contribution to journalArticlepeer-review

12 Scopus Citations

Abstract

Silicon (Si) is a promising anode material for high-energy-density lithium-ion batteries (LIBs), but its short calendar life and poor cycling performance prevent its large-scale adoption. Introducing magnesium (Mg) salt into the electrolyte has been recently shown to form a ternary Li-Mg-Si Zintl phase upon lithiation of Si and improve the cycling performance. However, the ternary Zintl phase formation mechanism and its impact on the solid electrolyte interphase (SEI) are not yet well understood. Here, we demonstrate the formation of a ternary Li-Mg-Si Zintl phase by Mg coating of the Si anode, where Mg diffuses into the Si film upon deposition and intermixes further during the lithiation process. The presence of the Zintl phase improves the interface stability, alters the nature of the SEI, and enhances the cycling performance of the Si anode. This study provides insights into the formation mechanism of the ternary Zintl phase and guidelines for the future design of Si anodes.

Original languageAmerican English
Pages (from-to)11534-11539
Number of pages6
JournalACS Applied Energy Materials
Volume3
Issue number12
DOIs
StatePublished - 28 Dec 2020

Bibliographical note

Publisher Copyright:
© 2020 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-76811

Keywords

  • high interface stability
  • Li-ion batteries
  • Mg coating
  • Si thin film electrode
  • ternary Li-Mg-Si Zintl phase

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