Graphite-FeSi alloy composites as anode materials for rechargeable lithium batteries

摘要

Iron-silicon are prepared by annealing elemental mixtures at 1000℃ followed by mechanical milling. Graphite-Fe_(20)Si_(80) alloy composites have been prepared by ball-milling a mixture of Fe_(20)Si_(80) alloy and graphite powder. The microstructure and electrochemical performance of the composites are characterized by X-ray diffraction and an electrochemical method. The FeSi_2 matrix is stable for extended cycles and acts as a buffer for the active centre, Si. The Fe_(20)Si_(80) alloy electrode delivers large initial capacity, but the capacity degrades rapidly with cycling. Fe_(20)Si_(80) alloy-graphite composite electrodes, however, show good cycleability and a high reversible capacity of about 600 mAh g~(-1). These composites appear to be promising candidates for negative electrodes in lithium rechargeable batteries.