Solution route synthesis of InSb, Cu 6Sn 5 and Cu 2Sb electrodes for lithium batteries

Abstract

A solution method was used to prepare InSb, Cu 6Sn 5 and Cu 2Sb 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. Cu 2Sb 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 Cu 2Sb electrodes.