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

Silicon (Si) anodes are considered promising candidates for next-generation lithium-ion batteries (LIBs) due to their high theoretical capacity (≈10 times that of graphite). However, the substantial volume expansion during cycling (>300%) results in the degradation of the solid electrolyte interphase (SEI) and pulverization of Si anodes. Herein, an AlF₃ coating layer is introduced onto commercial Si-C composites (Si-C@AF-x) as an artificial SEI layer, which effectively modulates the interfacial environment with higher kinetics and stability. The Si-C@AF-1 anode achieves excellent cycling stability (capacity of 916.0 mA h g^-1  after 100 cycles at 0.5 C and retention of 91.6%) and rate capability (549.7 mA h g^-1 at 3.0 C). Even under extreme temperatures, the AlF₃ coating layer can still support the fast and stable operation of the Si-C@AF-1 electrode, and the Si-C@AF-1||NCM811 full cell delivers 85.2% capacity retention after 100 cycles at 0.5 C. This work proves the effectiveness of designing a robust artificial SEI for enhancing the interfacial kinetics and stability, which also fits well with the commercial-scale production of electrode materials, thereby highlighting its strong commercialization potential for high-durability LIBs. © 2025 Wiley-VCH GmbH