Vertically Fluorinated Graphene Encapsulated SiO_x Anode for Enhanced Li⁺ Transport and Interfacial Stability in High-Energy-Density Lithium Batteries

Achieving high energy density has always been the goal of lithium-ion batteries (LIBs). SiO_x has emerged as a compelling candidate for use as a negative electrode material due to its remarkable capacity. However, the huge volume expansion and the unstable electrode interface during (de)lithiation, hinder its further development. Herein, we report a facile strategy for the synthesis of surface fluorinated SiO_x (SiO_x@vG-F), and investigate their influences on battery performance. Systematic experiments investigations indicate that the reaction between Li⁺ and fluorine groups promotes the in situ formation of stable LiF-rich solid electrolyte interface (SEI) on the surface of SiO_x@vG-F anode, which effectively suppresses the pulverization of microsized SiO_x particles during the charge and discharge cycle. As a result, the SiO_x@vG-F enabled a higher capacity retention of 86.4 % over 200 cycles at 1.0 C in the SiO_x@vG-F||LiNi_0.8Co_0.1Mn_0.1O₂ full cell. This approach will provide insights for the advancement of alternative electrode materials in diverse energy conversion and storage systems.