Sn/C纳米复合材料的合成及其电化学嵌放锂性能

用SnCl4和葡萄糖的水热反应合成SnO₂/碳质复合材料,然后在氮气气氛中热处理使SnO₂被碳热还原为Sn纳米粒子,制备得到Sn/C纳米复合材料.用X-射线衍射(XRD), 透射电镜(TEM)和X-射线电子散射能谱(EDX)对样品进行表征.结果显示Sn纳米粒子具有球形的形貌,并均匀地分散在无定形的碳材料中.对于Sn质量分数58.5%和32.3％的Sn/C复合材料,Sn纳米粒子的平均粒径分别为51和20 nm.电化学测试结果显示,Sn/C复合材料具有高的电化学贮锂可逆容量和良好的循环稳定性.讨论了Sn/C纳米复合材料的形成机理及其循环稳定性能改善的原因.

Synthesis of Sn/C nanocomposites and their electrochemical performances as anode materials of Li-ion battery

The SnO₂/carbonaceous composites were firstly prepared by the hydrothermal reaction between SnCl₄ and glucose. Sn/C nanocomposites were obtained after the treatment of the SnO₂/carbonaceous composites in N₂ gas flow, during which SnO2 was reduced to Sn nanoparticles by carbon thermal reduction. The products were characterized by XRD, TEM and EDX. The results shows that the Sn nanoparticles are spherical and dispersed in amorphous carbon materials. The mean diameters of Sn nanoparticles are 51 nm and 20 nm, respectively, for the Sn/C composites with Sn of 58.5wt% and 32.3wt%. Electrochemical tests demonstrate that the Sn/C nanocomposite electrodes exhibit high reversible capacity and good cycling performances used as anode materials of Li-ion battery. The mechanisms of the formation of Sn/C nanocomposites and the improvement in their cycling performances were also investigated.