Effect of processing on microstructure and electrochemical performance of silicon/disordered carbon/carbon nanotubes composites

Abstract

As an anode material for lithium-ion batteries, silicon/disordered carbon/carbon nanotubes composites were prepared by a sucrose-aided combustion method using two different mixing methods, namely mechanical stirring and ball milling. In this study, sucrose was used as a carbon source. The as-prepared composites were characterized by means of X-ray diffraction, field emission scanning electron microscopy, and electrochemical impedance spectroscopy. Both composites contain silicon and a small amount of carbon as predominating phases. The SDC-M composite prepared using mechanical stirring shows higher cycle performance (834.8 mAh/g) and first charge/discharge efficiency (72.4%) than the SDC-B composite prepared using ball milling (cycle performance of 815.2 mAh/g and first charge/discharge efficiency of 68.8%). The difference in the electrochemical performances of the SDC-M and SDC-B composites can be attributed to the distribution of carbon nanotubes and silicon particles in the disordered carbon matrices, which was greatly affected by mixing method.