Solution route synthesis of InSb, Cu6Sn5 and Cu2Sb electrodes for lithium batteries

A solution method was used to prepare InSb, Cu6Sn5 and Cu2Sb intermetallic compounds that are of interest as negative electrode materials for lithium batteries. The compounds were synthesized by the reduction of dissolved transition metal- and metalloid salts with fine Zn powder. Heterogeneous redox reactions at the surface of the Zn particles resulted in fern-like dendritic structures with high surface areas. Powder X-ray diffraction and lattice imaging by transmission electron microscopy showed that the intermetallic products were highly crystalline with preferred crystallographic orientations. Mild heat-treatment of the products under argon improved their phase purity. Electrodes prepared by this method exhibited a large irreversible capacity loss on the first charge/discharge cycle. Cu2Sb electrodes showed the greatest cycling stability; after the initial cycle, they delivered more than 230 mAh g−1 when cycled between 1.2 and 0.0 V versus metallic lithium, consistent with previously reported data for ball-milled Cu2Sb electrodes.