Mechanically milled nanocrystalline Ni3Sn4 and FeSi2 alloys as an anode material for Li-ion batteries

Nanocrystalline Ni3Sn4 and FeSi2 have been synthesized by high energy ball-milling and their electrochemical properties have been examined with respect to their performance as new anode materials for lithium-ion batteries. A comparison was made between the mechanically milled nanocrystalline and the subsequently annealed microcrystalline electrodes. High energy ball-milled nanocrystalline powder exhibits a large first discharge capacity of 1515 mAh/g and 1129 mAh/g for Ni3Sn4 and FeSi2, respectively. The irreversible capacity loss happens primarily during the first charge/discharge cycle in the nanocrystalline powders. Although initial capacity decreases rapidly in the early stage of charge/discharge cycling, the nanocrystalline FeSi2 exhibits higher irreversible lithium capacities than the annealed microcrystalline powders.