硫化钨基纳米材料锂化/退锂化及电化学性能影响因素研究

项目名称： 硫化钨基纳米材料锂化/退锂化及电化学性能影响因素研究

项目编号： No.11504331

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 许婷婷

作者单位： 郑州大学

项目金额： 21万元

中文摘要： 商用化锂电池负极材料石墨具有结构稳定、导电性好等优点，但其比容量不能满足大型功耗设备的需要。WS2具有与石墨类似的层状结构，且具有层间距大、比容量高的优势，但目前存在的容量退化快、循环性能差等问题严重限制了其实际应用。以WS2纳米材料为负极的锂电池电化学性能与其锂化/退锂化过程中WS2的结构演变以及由此产生的应力息息相关，然而当前未见系统的相关研究报道。本课题拟通过将分析锂电池充放电产物结构和成分的常规方法与透射电子显微镜/扫描电子显微镜中的原位手段相结合，研究WS2纳米材料的锂化/退锂化过程，判定其电化学反应机理并探讨电化学性能变差的影响因素。同时，基于WS2/碳复合材料中两种组分发生协同作用从而提高电化学性能这一实验事实，针对锂化/退锂化时WS2纳米管和碳组成复合材料的结构、成分、力学性能变化展开系统的原位研究。本课题的研究结果将为改善WS2基纳米材料的电化学性能提供重要依据。

中文关键词： 硫化钨；锂化；电化学性能；原位研究

英文摘要： Graphite, the current commercial anode material of lithium-ion batteries (LIBs), has a stable structure, a good conductivity etc., but it’s specific capacity can’t meet the needs of large-scale power equipments. Tungsten disulfide (WS2), which has a graphite-like layered structure, possesses a larger interlayer spacing and a higher specific capacity. However, fast capacity degradations and poor cycling performance have appeared in LIBs with WS2 as anodes, which severely limits the practical application of WS2. The electrochemical performance of LIBs with WS2 nanomaterials as anodes is closely related to WS2 nanomaterials’ structural change and the consequent stress during lithiation/delithiation, but so far no systematic research has been reported. Through combining in-situ study in transmission electron microscope/scanning electron microscope with the conventional method of analyzing charging/discharging products’ structure and composition in LIBs, this project intends to study the lithiation/delithiation process of WS2 nanomaterials, to determine the electrochemical reaction mechanism and to explore the influencing factors of electrochemical performance degradations. The experiment results show that WS2/carbon composites have an improved electrochemical performance by the synergistic effect between different constituents. On this basis, this project will carry out systematic in-situ study on the structure, composition and mechanical property in WS2 nanotubes/carbon composites during lithiation/delithiation. The results of this subject will provide an important reference on how to improve electrochemical performance of WS2-based nanomaterials.

英文关键词： tungsten disulfide;lithiation;electrochemical performance;in-situ study