LiF-coated Fe₂O₃ nanospheres as stable anodes for lithium-ion batteries

Iron oxide (Fe₂O₃), possessing a high theoretical capacity, is considered a promising anode material for lithium-ion batteries (LIBs). However, its practical application is hampered by poor cycling stability and rate capability, primarily caused by severe volume changes during cycling and the formation of an unstable solid electrolyte interphase (SEI). Herein, a LiF coating was constructed on Fe₂O₃ nanospheres via a mild liquid-phase method. The Fe₂O₃@LiF electrode exhibited a high capacity of 283 mAh g^-1 at 5.0 A g^-1 in rate performance evaluation, far exceeding the 102 mAh g^-1 of Fe₂O₃. After 500 cycles at 2.0 A g^-1, the Fe₂O₃@LiF electrode still delivered a high reversible capacity of 709 mAh g^-1, whereas the Fe₂O₃ electrode decreased to only 310 mAh g^-1, confirming its enhanced rate capability and long-term cycling stability. Electrochemical impedance spectroscopy (EIS) reveals a marked reduction in charge-transfer resistance (R_ct) from 126 Ω (Fe₂O₃) to 55 Ω (Fe₂O₃@LiF), highlighting improved interfacial charge transport enabled by the LiF coating. This facile surface coating strategy provides an effective approach for developing high-performance metal oxide anodes.