Enhancement of Cycle Performance of Si/TiFeSi2 Nanocomposite As Lithium Storage Material By Mechanical Deformation

Abstract

Although silicon has higher reversible capacity than graphite as a lithium storage material, its large volume change during lithium insertion and extraction causes poor capacity retention. To address this technical issue, melt-spun Si based alloy materials have been suggested as promising materials for lithium ion batteries because of their high capacity and relatively low production cost. However, their long-term cycle performance should be further improved for the commercial success. In this study, it is demonstrated that mechanical deformation can improve the electrochemical performances of melt-spun Si alloy material. By applying the high-energy mechanical milling to melt-spun Si/TiFeSi2, Si/TiFeSi2 nanocomposite is successfully modified with a size of few nanometer, and that is clearly observed by X-ray diffraction (XRD) and transmission electron microscope (TEM). As s result, the microstructurally tuned Si/TiFeSi2 showed a reversible capacity of more than 1000 mAh g-1 with stable capacity retention up to 100 cycles. More detailed studies on the reasons for better cycle performance of milled Si/TiFeSi2 will be discussed in this presentation.