Pre-Fluorination Interface Engineering of Silicon-Based Anode for Durable Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high capacity for lithium-ion batteries (LIBs) but suffer from volume expansion and degradation.
• The solid electrolyte interphase (SEI) layer is crucial for anode stability but often unstable in silicon anodes.
• Developing robust artificial SEI layers is key to overcoming silicon anode limitations.

Purpose of the Study:

• To enhance the stability and performance of silicon anodes in LIBs.
• To investigate the effectiveness of an aluminum fluoride (AlF3) coating as an artificial SEI layer.
• To assess the cycling stability, rate capability, and performance under extreme temperatures.

Main Methods:

• Coating commercial Si-C composites with AlF3 to create Si-C@AF-x materials.
• Electrochemical testing including cycling stability and rate capability measurements.
• Fabrication and testing of Si-C@AF-1||NCM811 full cells.

Main Results:

• The Si-C@AF-1 anode demonstrated excellent cycling stability with 916.0 mA h g⁻¹ capacity and 91.6% retention after 100 cycles at 0.5 C.
• High rate capability was achieved, delivering 549.7 mA h g⁻¹ at 3.0 C.
• The AlF3 coating ensured stable performance even at extreme temperatures, and the full cell retained 85.2% capacity after 100 cycles.

Conclusions:

• AlF3 coating effectively functions as an artificial SEI, enhancing interfacial kinetics and stability for silicon anodes.
• The developed Si-C@AF-1 material shows strong potential for commercialization in high-durability LIBs.
• This strategy provides a viable pathway for advancing silicon anode technology in next-generation batteries.