MgF2 Interface Engineering Promotes the Growth and Stability of LiF-Rich Solid-Electrolyte Interphases on Si-C

Peng Liu; Yupeng Xiao; Jiyuan You; Bo Zhang; Tianle Li; Xiaotong Gao; Yuqian Li; Wenju Wang

doi:10.1021/acsami.4c11705

MgF₂ Interface Engineering Promotes the Growth and Stability of LiF-Rich Solid-Electrolyte Interphases on Si-C

ACS Appl Mater Interfaces. 2024 Oct 30;16(43):59488-59496. doi: 10.1021/acsami.4c11705. Epub 2024 Oct 21.

Authors

Peng Liu^{1

2}, Yupeng Xiao^{1

2}, Jiyuan You^{1

2}, Bo Zhang^{1

2}, Tianle Li^{1

2}, Xiaotong Gao^{1

2}, Yuqian Li^{1

2}, Wenju Wang^{1

2}

Affiliations

¹ School of Energy and Power Engineering Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
² Energy and Technology Institute, Nanjing 210094, P. R. China.

PMID: 39429037
DOI: 10.1021/acsami.4c11705

Abstract

Volume expansion of the Si-C anode during the charging/discharging process causes continuous fracture/formation of the solid electrolyte interface (SEI), which leads to rapid capacity fading. Here, we designed a MgF₂-modified separator (MF-PP) to construct a fluorine-rich SEI layer by generating more LiF. The robust SEI layer formed can alleviate the volume stress and prevent crack growth in Si-C electrodes. After 450 cycles, the Si-C||MF-PP half cell retained a reversible capacity of 543.2 mAh g^-1, while the LFP||MF-PP||Si-C full cell maintained a reversible capacity of 103.4 mAh g^-1 with high Coulombic efficiency after 100 cycles. This facile and low-cost separator modification strategy provides an easily scalable approach to develop stable Si-based anodes for next-generation high-energy-density systems.

Keywords: LiF; MgF2 modified separator; Si-C anode; artificial SEI layer; lithium-ion batteries.