Facile synthesis of Si nanoparticles using magnesium silicide reduction and its carbon composite as a high-performance anode for Li ion batteries

A new method for a facile synthesis of nano-silicon/carbon mesoporous composite is proposed. Silicon nanoparticles can be obtained through the magnesium silicide reduction of amorphous silica using high energy mechanical milling process. And mesoporous carbon matrix is fabricated via simple carbon coating method on Si nanoparticles followed by chemical etching of preexisting magnesium oxide nano-particles. This nano-silicon/carbon mesoporous composite electrode shows an excellent electrochemical performance as an anode for lithium ion batteries, achieving a reversible capacity of c.a. 1600 mAh g^-1 over 50 cycles at a current of 1.0 A g^-1 and superior rate capabilities with reversible capacity of about 1530 mAh g^-1 at a discharge current density of 3 A g^-1.