Synthesis and electrochemical performance of novel loose structured submicro/micro-sized NiSnx alloy composites for lithium batteries

An effective method of carbothermal reduction was employed to prepare spherical microcrystal NiSnx alloy powders from oxides of Sn and Ni used as anode materials for Li-ion battery. According to XRD, SEM and TEM analysis, the synthesized spherical NiSnx powders show a loose submicro/micro-sized structure and a multi-phase composition. The prepared NiSnx alloy composite electrode exhibits a stable discharge capacity of electrode is ca. 380 mAh g−1 at constant current density of 50 mA g−1, and can be retained at 350 mAh g−1 after 25 cycles. Moreover, NiSnx alloys exhibit excellent high rate performance, i.e. stable discharge capacities of 300–310 mAh g−1 and the coulombic efficiencies of 97.5–99.5% have been obtained at the current density of 500 mA g−1. The loose submicro-sized particle structural characteristic and the Ni addition in Sn matrix should be responsible for the improvement of cycling stability of NiSnx electrode. The carbothermal reduction method is simple, low-cost and mass-productive, which should be viable to other alloy composite materials system of rechargeable lithium ion batteries.