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 language | American English |
---|---|
Pages (from-to) | 11534-11539 |
Number of pages | 6 |
Journal | ACS Applied Energy Materials |
Volume | 3 |
Issue number | 12 |
DOIs | |
State | Published - 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