Carbon-coated SiO2 nanoparticles as anode material for lithium ion batteries

A simple approach is proposed to prepare C-SiO(2) composites as anode materials for lithium ion batteries. In this novel approach, nano-sized silica is soaked in sucrose solution and then heat treated at 900 degrees C under nitrogen atmosphere. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis shows that SiO(2) is embedded in amorphous carbon matrix. The electrochemical test results indicate that the electrochemical performance of the C-SiO(2) composites relates to the SiO(2) content of the composite. The C-SiO(2) composite with 50.1% SiO(2) shows the best reversible lithium storage performance. It delivers an initial discharge capacity of 536 mAh g(-1) and good cyclability with the capacity of above 500 mAh g(-1) at 50th cycle. Electrochemical impedance spectra (EIS) indicates that the carbon layer coated on SiO(2) particles can diminish interfacial impedance, which leads to its good electrochemical performance. (C) 2011 Elsevier B.V. All rights reserved.