“…Silicon can alloy with lithium to form four different phases Li 12 Si 7 , Li 7 Si 3 , Li 13 Si 4 and Li 21 Si 5 , and the total theoretical capacity for the reaction of lithium and silicon to Li 21 Si 5 is 1967 mAh g −1 which corresponds to 4.2 mol lithium per mol silicon [12]. Silicon oxide [13,14], Si-based alloys such as SiAg [15,16], SiMg [17][18][19], SiCa [20], SiNi [21], SiFe [22] and Si/C composites [23][24][25] have been reported as anodes for lithium ion batteries. Though the cycle stability of Si-based materials was improved to some extent, the initial irreversible capacity loss was so large that they cannot be applied for commercial use.…”