Cycleable graphite/FeSi6 alloy composite as a high capacity anode material for Li-ion batteries

FeSi₆/graphite composite was prepared by mechanical ball milling. The FeSi₆ alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi₂, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800 mAh g⁻¹) and good cycleability, due to the buffering effect of the inactive FeSi₂ phase and graphite layers on the volumetric changes of Si phase during lithium–Si alloying reaction. Since FeSi₆ alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries.