Strengthening the Interfacial Stability of the Silicon-Based Electrode via an Electrolyte Additive─Allyl Phenyl Sulfone

Silicon-based anodes have received widespread attention because of their high theoretical capacity, which, however, still faces challenges for practical applications due to the large volume changes during repeated charge/discharge processes, despite being developed for many years. Herein, we explore an electrolyte additive, allyl phenyl sulfone (APS), to enhance the interfacial stability and long-term durability of the SiOx/C electrode. It is revealed that additive APS contributes to forming a dense and robust solid electrolyte interphase film with high mechanical strength and favorable lithium-ion diffusion kinetics, which effectively suppresses the parasitic side reactions at the electrode-electrolyte interface. Meanwhile, the strong interaction between APS and trace water/acid in the electrolyte is further beneficial for enhancing the interfacial stability. By incorporating 0.5 wt% APS, the cycling stability of the silicon-based electrode is significantly improved, reserving a capacity of 777 mAh g–1 after 200 cycles at 0.5C and 30 °C (79.3% capacity retention), which well exceeds that of the baseline electrolyte (57.8% capacity retention). More importantly, additive APS effectively promotes the cycling performance of the corresponding SiOx/C||NCM90 (LiNi0.9Co0.05Mn0.05O2) full battery. This work provides valuable understanding in developing new electrolyte additives to enable the commercial application of high-energy density lithium-ion batteries using silicon-based anodes.