Electrochemical lithium insertion in graphite containing dispersed tin–antimony alloys

Graphite/SnSb composites were prepared by solution-phase reduction of SnCl2 and SbCl5 in the presence of graphite powder using either t-BuONa-activated NaH or t-BuOLi-activated LiH. Crude and washed materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission gun-scanning electron microscopy (FEG-SEM). Electrochemical lithium insertion was carried out in both types of composites using voltammetry or galvanostatic charge/discharge techniques. It appeared that graphite-SnSb composites prepared using t-BuOLi-activated LiH as reductant displayed the highest reversible capacity (ca. 500 mA h g−1). This phenomenon is likely in relation with a better dispersion and grafting of metal particles on graphite, as suggested by FEG-SEM and TEM analyses. However, such dispersion appeared to increase significantly the irreversible capacity.