新型TiO_2(B)/碳复合纳米线负极材料电化学特性研究

Growth and Characterization of TiO_2(B)/C Composite Nanowire and Its Application as Anode Material in Li-Ion Battery

以锐钛矿TiO2粉末为原料,通过简单的两次水热及氩气气氛下热处理工艺,制备出新型TiO2(B)/碳一维复合纳米线材料。研究结果表明该复合纳米线主要是由TiO2(B)所组成,其外层包覆一层无定形碳以形成特殊的一维壳/核结构;这种特殊一维壳/核结构和化学组成在诸多领域都将会有着极其广泛应用。本文锂离子电池测试结果证实该复合纳米线电极具有超高的可逆循环电池容量和倍率充放电容量,在30 mAg-1充放电速率下,该TiO2(B)/碳一维壳核结构材料100圈循环后容量高达560 mAhg-1;在750 mAg-1充放电速率下,充放电容量达到200 mAhg-1。鉴于其优良的电化学性能,该一维复合结构材料有望成为下一代最有前途的锂离子电池电极材料。

A novel type of the TiO2（B）/C composite nanowire was developed by the two-step hydrothermal synthesis, followed by annealing in argon atmosphere. Various factors influencing the film growth were evaluated. The micmstmctures and electrochemical properties of the nano-wire were characterized with X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results show that the composite nanowires consist of the TiO2 core surrounded by amorphous carbon shell,and that it has favorable electrochemical properties. A prototyped Li-ion battery was fabricated with the TiO2（B）/C composite nanowire as the anode material. The nanowires display excellent cyclic performance and rate capacity. For example, after 100 cycles at a current density of 30 mAg^-1, its reversible capacity was found to be 560 mAhg^- 1 with excellent cycling stability and the rate capacity （200 mAhg^- 1, when cycled at 750 mAg^- 1 ）. We suggest that the TiO2（B）/C composite nanowire be a potential anode material for Li-ion battery.