Double-walled core-shell structured Si@SiO2@C nanocomposite as anode for lithium-ion batteries

Double-walled core-shell structured Si@SiO2@C nanocomposite has been prepared by calcination of silicon nanoparticles in air and subsequent carbon coating. The obtained Si@SiO2@C nanocomposite demonstrates a reversible specific capacity of about 786 mAh g(-1) after 100 cycles at a current density of 100 mA g(-1) with a capacity fading of 0.13 % per cycle. The enhanced electrochemical performance can be due to that the double walls of carbon and SiO2 improve the electronic conductivity and enhance the compatibility of electrode materials and electrolyte as a result of accommodating the significant volumetric change during cycles. The interlayer SiO2 may release the mechanical strain and enhance the interfacial adhesion between carbon shell and silicon core.