Nano-sized SnSbCu_x alloy anodes prepared by co-precipitation for Li-ion batteries

Nano-sized SnSbCu_x alloy anode materials are prepared by reductive co-precipitation method combining with the aging treatment in water bath at 80 °C. The microstructure, morphology and electrochemical properties of synthesized SnSbCu_x alloy powders are evaluated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and galvanostatical cycling tests. The results indicate that the average particle size is reduced and the Cu₆Sn₅, Cu₂Sb phases appear successively along with the increase of Cu content in the SnSbCu_x alloy. The reduction of average particle size, the existence of inactive element Cu and the complex multi-step reaction mechanism in SnSbCu_x alloy anodes are propitious to improve the structure stability and thus improve the cycling performance. When cycled at a constant current density of 0.1 mA cm^-2 between 0.02 and 1.50 V, the coulomb efficiency of first cycle exceeds 74% and the reversible capacity of 20th cycle attains to 490 mAh g^-1 in SnSbCu_0.5 alloy anode.