多级结构硫复合正极材料构筑及原位电化学反应机制研究

项目名称： 多级结构硫复合正极材料构筑及原位电化学反应机制研究

项目编号： No.51272156

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 王久林

作者单位： 上海交通大学

项目金额： 80万元

中文摘要： 具有高理论能量密度、低成本、环保等优势的锂硫二次电池已成为目前化学电源领域研究的热点之一，但硫正极材料循环性能差，一直制约着该电池的发展。针对单质硫材料导电性差和多硫离子溶解性强这两关键问题，本研究提出了构筑多级结构纳米硫复合材料，并对其电化学反应机制进行原位探究。将采用高度分散的石墨烯作为导电剂和结构基材，使单质硫以零维纳米点（＜10nm）钉扎在石墨烯活性点上；利用喷雾对上述纳米复合片进行组装，构筑具有多级结构的硫复合材料微球。零维纳米点的单质硫具有极高的电化学活性，含有大量活性点的石墨烯以及多壳层结构能有效地抑制多硫离子的溶解和扩散，从而将单质硫和多硫离子限域在纳米尺度空间。同时，采用EC-SPM原位技术探究硫正极材料放电/充电过程中多硫离子溶解和扩散、穿梭和硫沉积机制。预期获得高能量密度和长循环寿命的硫正极材料，为进一步研发高能电池材料奠定良好的科学基础。

中文关键词： 硫正极材料；石墨烯纳米片；多级结构；多功能粘接剂；安全性电解质

英文摘要： Lithium/sulfur (Li/S) battery became one of hot topics recently in the field of electrochemical power sources because of its obvious advantages of high theorectical energy density (2567 Wh/kg based on electrode materials), low cost and environmental benignity. However, the poor cycling properties of the sulfur cathode materials impede its practical applications. The critical problems of sulfur cathode materials lie in the dissolution of discharge products polysulfides during charge/discharge process, and its poor electric conductivity. This project proposes to construct a hierarchical microstructure for nano sulfur composite materials, and to investigate its electrochemical reaction mechanism via in-situ techniques. Highly dispersed graphene nano sheet (GNS) will be used as conductive matrix and elemental sulfur in the form of zero-dimension dot (less than 10nm) will be pinned on the active points of GNS. In the following, hierarchical microspheres will be constructed via spraying and self-assembling. Elemental sulfur with zero-dimension possesses high electrochemical activity. GNS with its abundant active points and multi shells can effectively suppress the dissolution and diffusion of polysulfides, and restrain elemental sulfur and polysulfides within nano meter dimension. Moreover, in-situ techniques, particu

英文关键词： Sulfur composite cathode；Graphene nano sheet；Hierarchical structure；Multi-functional binder；Safe electrolyte