F-doped Carbon Coated Nano-Si Anode with High Capacity: Preparation by Gaseous Fluorination and Performance for Lithium Storage

Si anodes hold immense potential in developing high-energy Li-ion batteries.But fast failure due to huge volume change upon Li uptake impedes their application.This work reports a facile yet low-toxic gas fluorination way for yielding F-doped carbon-coated nano-Si anode materials.Coating of nano-Si with F-doped carbon containing high defects can effectively protect Si from huge volume change upon Li storage while facilitating Li + transport and formation of stable LiF-rich solid electrolyte interphase (SEI).This anode exhibits high capacities of 1540-580 mAh•g -1 at various current rates of 0.2-5.0A•g -1 , while retaining >75% capacity after 200 cycles.This method also addresses the issues of high cost and toxicity of traditional fluorination techniques that use fluorine sources such as XeF 2 and F 2 .