碳包覆NbSn_2贮锂材料的制备和性能

Preparation and properties of carbon-coated NbSn_2 as lithium storage material

用机械球磨-热解法制备了碳包覆NbSnz贮锂材料。通过X射线衍射光谱法（XRD）、透射电子显微镜法（TEM）和电化学测试对材料进行了表征，用非原位XRD测试研究了材料的反应机理。所制备的材料粒径大小分布在0．5～1．5μm-材料表面碳的包覆较均匀，包覆厚度为30-60nm。在充放电电压1．5-0V内，初始可逆充电比容量为701mAh／g。经过20周的循环后，充电比容量仍然保持为524mAh／g。与没有碳包覆的铌锡负极材料相比。其贮锂容量和循环性能都大大提高。

Carbon-coated NbSn2 alloy powers were synthesized as lithium storage material by ball-milling and pyrolysis methods. The product was characterized by XRD, TEM and electrochemical measurements. The reaction mechanism was studied with ex-situ XRD tests. The size of the particles is in the range of 0.5--1.5 μm, and carbon coating is comparatively more uniform with 30-60 nm thickness. The initial reversible charge specific capacity is 701 mAh/g and the charge specific capacity remains 524 mAh/g in the 20th cycle when the battery is discharged and charged at 1.5-0 V. The results show that carbon-coated NbSn2 alloy exhibits better lithium storage capacity and cycle property than uncoated NbSn2 anode materials.