Functional electrolytes enhancing electrochemical performance of Sn–Fe–P alloy as anode for lithium-ion batteries

•The LiBOB-derived SEI contains hydrocarbon, ethers, carbonates, and LixPFy/LixPFyOz.•VC makes the SEI mainly consisted of ethers and carbonates.•FEC-derived SEI with LiF and less organic species were capable of achieving stable cycling properties of anodes.

To enhance the electrochemical properties of the Sn3.95Fe0.05P3 anode, we focus on reducible additives to mitigate damage to the anode by electrolyte decomposition. It is found that the the electrochemical performance of the anode is significantly improved when formulated with an FEC-added electrolyte. Ex-situ X-ray photoelectron spectroscopy (XPS) reveals that the FEC additive builds an LiF-based solid electrolyte interphase (SEI) with less organic species on the anode upon cycling.