Simple synthesis of Si/Sn@C-G anodes with enhanced electrochemical properties for Li-ion batteries

A silicon/tin@amorphous carbon-graphite (Si/Sn@C-G) composite material was successfully prepared by a simple high energy ball milling and annealing process , exhibiting excellent electrochemical performance in lithium-ion batteries. Structural characterization showed that the phase separated Si/Sn mixture was coated by amorphous carbon and were highly dispersed into the graphitic sheets. As a result, the Si/Sn@C-G composite exhibited a high initial coulombic efficiency of 81.5% and a stable reversible capacity of 612.6 mAh g −1 even after 100 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy results indicated that the Sn acted as an active matrix and could obviously decrease the polarization resistance (Rp). And the ductile Sn could not only cushion the volumetric deformation of Si, but could also improve the Si dispersion. This work demonstrated a facile approach to synthesize highly stable Si/Sn@C-G composite in lithium-ions batteries.