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

Abstract

An effective method of carbothermal reduction was employed to prepare spherical microcrystal NiSn x 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 NiSn x powders show a loose submicro/micro-sized structure and a multi-phase composition. The prepared NiSn x 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, NiSn x 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 NiSn x 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.