Preparation and Electrochemical Properties of Si@SiO2/N Doped Carbon Composites
Author:
Affiliation:
1.College of Materials Science and Technology, Nanjing University of Aeronautics & Astronautics,Nanjing，211106,China;2.School of Physics, Southeast University,Nanjing，211189,China
A core-shell Si@SiO2@NC (N-doped carbon) composite material is proposed for improving the performance of silicon-based lithium-ion battery resulting from the volume expansion and poor conductivity of Si during the charge and discharge processes. SiO2 layer is prepared by treating the surface of Si nanoparticles with oxygen plasma, and N-doped amorphous carbon is obtained by carbonizing the polyaniline coating. The SiO2 interlayer has a reliable buffer effect and good mechanical support to restrain the volume expansion of Si nanoparticles during charge and discharge processes, and N-doped amorphous carbon can serve as a fast transport channel for electrons and Li+. Compared with Si nanoparticles, Si@SiO2@NC composites show a high initial discharge capacity of 2 583.1 mAh/g with Coulombic efficiency of 81% as well as a high reversible capacity of 1 015 mAh/g at a current density of 200 mA/g after 40 cycles.