Mo3Sb7-C Composite Anodes for Lithium-Ion Batteries

Mo3Sb7-C composite has been synthesized by first firing a mixture of Mo and Sb metals and then ball-milling the resultant material with carbon. X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) data reveal that these composites are composed of uniformly dispersed, submicrometer sized, crystalline Mo3Sb7 in a conductive carbon matrix. The presence of carbon in the composite drastically improves the cycle life of Mo3Sb7 as the carbon buffers the volume changes occurring during charge-discharge cycling. With a discharge capacity of 518 mAh/g and 907 mAh/cm(3) and a tap density of 1.75 g/cm(3) for the composite, the Mo3Sb7-C composite anodes offer three times higher volumetric capacity than the graphite anode. Also, with an operating voltage (similar to 0.8 V) well above that of Li/Li+, the Mo3Sb7-C composite anodes offer better safety.