S@TiO2纳米颗粒/纳米管正极材料的设计合成及其固硫机制研究

项目名称： S@TiO2纳米颗粒/纳米管正极材料的设计合成及其固硫机制研究

项目编号： No.51302219

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 谢科予

作者单位： 西北工业大学

项目金额： 25万元

中文摘要： 单质硫正极材料具有1675 mAhog-1的理论比容量，但极低的电子电导率、充放电过程中大的体积变化及反应中间产物多硫化物的"穿梭效应"严重制约了其容量发挥和循环稳定性。本项目拟采用独特的材料结构设计，以阳极氧化TiO2纳米管为骨架，通过调节"水诱导自组装"、"低温煅烧+二次阳极氧化"、氢处理及注硫工艺参数，制备具有预留孔容的硫@二氧化钛纳米颗粒/纳米管（S@TiO2NP/NT）正极材料。利用氢处理提高TiO2NP/NT材料的电子电导率；利用预留孔容及TiO2纳米管缓和充放电过程中硫的体积变化；利用TiO2颗粒吸附固定多硫化物。通过本项目研究建立结构、性能可控的正极材料制备技术，揭示材料微观结构与电化学性能间的构效关系，揭示TiO2对多硫化物溶解的影响规律，阐明其对多硫化物的吸附固定机制，为高比容量、高循环稳定性锂硫电池正极材料的设计合成与开发应用提供新的思路和科学依据。

中文关键词： 锂硫电池；固硫机制；正极材料；循环稳定性；二氧化钛

英文摘要： Sulfur is an attractive cathode material with a high specific capacity of 1675 mAhog-1, however its poor electronic conductivity, large volumetric expansion and dissolution of intermediate polysulphides, which result in a low utilization of active material and rapid capacity decay. In this project, we have designed a new type of S@TiO2 nanoparticle/nanotube(S@TiO2 NP/NT) cathode materials by a multi-step fabrication process: first, anodic TiO2 NT was aged by H2O, and then followed by a thermal treatment and subsequent anodization to obtain free-standing TiO2 membranes with both ends open. After treated in H2 atmosphere, the sulfur was infused by a solvent method. In such an electrode, each part plays its desired role, with the hydrogenated TiO2 being fast electron conducting path, TiO2 NT working as a capsule to limit the large volumetric expansion of sulphur, and the TiO2 NP absorbing the soluble lithium polysulfides. Efforts will be devoted to developing new fabrication technology of sulfur-based cathode materials with strong control ability of the structure and performance in this study. Besides, the relationship between the microstructure and electrochemical performances of the S@TiO2 NP/NT would be established. It would be verified that how the TiO2 influence the solubility of polysulfides. And the mechanis

英文关键词： Li-S batteries；polysulfides anchoring；cathode material；cycle stability；TiO2