Carbon/Ba-Fe-Si alloy composite as high capacity anode materials for Li-ion batteries

A novel Ba-Fe-Si/C composite was prepared by mechanical ball milling and lithium insertion reactions on the composite electrode were investigated by cyclic voltammetry, charge-discharge measurements, XRD and XPS spectroscopy. It is demonstrated that the composite electrode not only possesses sufficiently high reversible capacity of ca. 420 mA h/g, but also exhibits strong capacity retention with indiscernible capacity decay during charge-discharge cycling. The improved cycling ability of the composite is suggested from a cooperative action by inactive FeSi2 and BaSi2 matrix and outer graphite shell, which both buffer the volumetric changes of the active Si phase and provide a good connection for electronic and ionic conduction during lithium insertion and extraction processes. (C) 2003 Elsevier B.V. All rights reserved.