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.