纳米TiO_2锂离子电池负极材料的溶剂热法制备及其电化学性能

Solvothermal Synthesis and the Electrochemical Property of Nano-sized TiO_2 Anode Materials for Lithium-ion Batteries

本文采用溶剂热法,以四乙醇钛为主要原材料制备TiO2。结合X-射线衍射和扫描电镜等材料结构测试分析方法和恒电流充放电电化学测试技术,研究了添加表面活性剂聚乙烯吡咯烷酮(PVP)、溶剂热反应温度和高电导性气相生长碳纤维(VGCF)的添加对TiO2结构和电化学性能的影响。研究结果表明,本方法成功制备了纳米尺寸的锐钛矿TiO2,PVP的添加能改善TiO2颗粒的分散性。较低溶剂热反应温度下合成的TiO2颗粒尺寸较细,但团聚程度大,而较高的溶剂热反应温度使TiO2的颗粒尺寸长大,但团聚程度改善。通过添加表面活性剂、控制溶剂热温度和引入VGCF,本文获得的TiO2/C复合材料作为锂离子电池负极材料在1C、5C、10C和20C的放电倍率下容量分别可达220、180、150和120mAh/g,具有良好的倍率性能。

TiO2 has been synthesized via a solvothermal method by using a titanium ethoxide of Ti(OEt)4 as the main raw material.Effects of the addition of surfactant of polyvinylpyrrolidone(PVP),the solvothermal temperature and the introduction of vapor growth carbon fiber(VGCF)on the structure and electrochemical properties of the TiO2 were investigated by means of X-ray diffraction,scanning electron microscopy,and electrochemical testing of galvanostatic charge-discharge,etc.The results show that nano-sized anatase TiO2 has been successfully synthesized by the present method.The addition of PVP improves effectively the dispersion of the TiO2 particles.The TiO2 particles synthesized at lower solvothermal temperature show smaller size but severer agglomeration,while those synthesized at higher solvothermal temperature show larger size but less agglomeration.By means of adding PVP,optimizing solvothermal temperature and introducing VGCF,the TiO2 shows high rate-capability as anode material for lithium-ion batteries,possessing capacities of 220,180,150 and 120mAh/g at discharge rates of 1C,5C,10 Cand 20C,respectively.