Fluorine-functionalized core-shell Si@C anode for a high-energy lithium-ion full battery

Highlights: • A fluorine functionalized core-shell structure of Si@C anode is prepared. • The influence of fluorine-functionalizing on the Si-based anode is first illuminated. • The composite exhibits acceptable cycling and rate capability in lithium-ion battery. • A new concept of high energy full battery is proposed and successfully assembled. -- Abstract: To illuminate the effect of F on a carbon coating and the surface modification process of the bulk, a fluorine functionalized core-shell silicon-carbon composite (Si@C) is prepared by a high-temperature pyrolysis process using PVDF and nano-Si as raw materials. By using PVDF, simultaneous modification of the core-shell silicon-carbon composite is realized, and a good theoretical model is established for the electrochemical behavior after fluorine modification, especially the surface and interfacial reaction of the Si-based anode. When the Si@C composite is used as an anode material in a lithium-ion battery, it delivers a reversible capacity of 683 mAh/g at 200 mA/g and a capacity retention of 67% after 50 cycles. A high-energy lithium-ion full battery configured from the Si@C anode and commercial LiNi_0.6Co_0.2Mn_0.2O₂ (Si@C LiNi_0.6Co_0.2Mn_0.2O₂) delivers an energy density that reaches 335.1 Wh/kg (vs. the cathode), making it a bright prospect for the regulation and control of interfacial/surface reactions in Si-based energy storage systems.