Hierarchical SnO₂ nanoflowers assembled by atomic thickness nanosheets as anode material for lithium ion battery

Abstract

Hierarchical SnO₂ nanoflowers assembled by atomic thickness nanosheets were prepared by facile one-pot solvothermal method with acetone/water mixture as solvent. The crystal structure, morphology and the microstructure of the as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and atomic force microscope (AFM). Results revealed that the nanoflowers (2–4 μm) were assembled by the ultrathin SnO₂ nanosheets (3.1 nm estimated by AFM). When tested as anode material for lithium ion batteries, the SnO₂ nanoflowers showed improved cycling stability comparing with the commercial SnO₂ particles. The reversible charge capacity of SnO₂ nanoflowers maintained 350.7 mAh/g after 30 cycles, while that of the commercial SnO₂ was only 112.2 mAh/g. The high reversible capacity and good cycling stability could be ascribed to the hierarchical nanostructure, atomic thickness nanosheets and large surface area of the SnO₂ nanoflowers.

摘要

便携式电子设备和电动汽车等的发展对高性能电池的需求日益迫切。锂离子电池由于其高能量密度,长循环寿命,环境友好等优点受到广泛关注。决定锂离子电池性能的重要因素是电极材料。SnO₂因其具有较高的理论容量、较低的嵌锂电压,常被用作负极材料。但是商品化SnO₂在嵌/脱锂过程中引起的体积变化会导致材料的聚集和粉末化,使材料的电化学性能大大减弱。构建纳米结构的SnO₂可以缓解这个问题。最近的研究表明二维原子层厚度纳米片具有优异的电化学性能,由此我们得到启发,通过一步溶剂热法合成了原子层厚度纳米片组装而成的SnO₂纳米花。该纳米花用作锂离子电池负极材料,显示出较大的可逆容量和良好的循环性能。SnO₂纳米花良好的电化学性能与SnO₂纳米花具有疏松结构、超薄原子层厚度的纳米片、大的比表面积等有关。与商品化SnO₂相比较,SnO₂纳米花电化学性能得到显著提高。