Self-sacrificed Synthesis of Amorphous Carbon-Coated SiOx as Anode Materials for Lithium-Ion Batteries

Amorphous carbon coated SiO x is developed by the self-sacrifice of self-assembled Nafion/SiO 2 and explored as anode materials for lithium-ion batteries to overcome the sever pulverization and the resultant loss of specific capacity caused by the volume expansion of Si during the lithium ions insertion/extraction process. The amorphous carbon coated SiO x (SiO x /C) is prepared by using selfassembled Nafion/SiO 2 as the precursor, following by magnesium reduction of SiO 2 and carbonization of Nafion ionomers. XPS, TEM and XRD results indicate that most of SiO x was reduced to amorphous Si 0 with small amount of Si 2+ and Si 4+ , which are coated by amorphous carbon. As the amorphous carbon coating can effectively reduce the volume change of SiO x -based material during the chargedischarge process and enhance the electronic conductivity of the material, the Nafion-derived amorphous carbon coated SiO x exhibits improved reversible capacity, better cycling stability and rate capability than that of pure amorphous carbon at Si loading below 10 wt%