锂硫电池已成为最具应用潜力的下一代高比能二次电池。然而，硫电导率低、多硫化锂溶出飞梭和锂枝晶等问题，使目前锂硫电池未能达到商业应用要求。本项目拟构建一类基于高活性富硫TexSeySz分子和多功能载体的高硫载量复合正极材料及其高性能锂硫电池。采用电导率和可极化率高的Se/Te掺杂S，本质上提高链状或环状TexSeySz的传导性和分子极性，通过杂原子耦合效应及其固硫作用，增强硫基正极材料电化学活性；利用多功能载体中丰富的MoS2界面缺陷，极大提高三维多孔载体的极性吸附和电催化活性，通过其疏堵并重策略，有效解决多硫属化锂溶出问题；采用Se/Te掺杂锂负极SEI膜，通过硫硒碲化有机/无机复合SEI膜高效抑制锂枝晶生长。在此基础上，确立高硫载量、高容量、高效率和长寿命锂硫电池的实现途径；阐明基于界面缺陷化学、具有疏堵并重策略的多功能载体的贡献作用；揭示基于高活性富硫TexSeySz分子的固硫新机制。

Lithium-sulfur battery has become one of the most promising rechargeable batteries for next-generation high-energy storage applications. However, because of the drawbacks such as the poor electronic conductivity of elemental sulfur, the dissolution/shuttle of polysulfides and the dendrite growth on Li metal anodes, Li-S batteries are far from ideal for commercial applications. In response to these challenges, this project will construct a new class of high-sulfur-loading composite cathode material based on the high-active and sulfur-rich TexSeySz molecules and the multi-functional hosts for Li-S batteries. Firstly, rational heteroatomization of the TexSeySz chain or ring molecules through doping Se or/and Te which have higher electronic conductivity and polarizability than S into sulfur molecules, will intrinsically improve the conductivity and polarity of TexSeySz. These synergistic effects in TexSeySz and their resultant immobilization ability of sulfur will enhance the electrochemical activity of TexSeySz composite cathode materials. Then, rational multi-functionalization of the hosts will not only ensure three-dimensional porous structures to store a large amount of TexSeySz, but also provide defect-rich MoS2, which will greatly strengthen the chemisorption effect of polychalcogenides and catalytic activity on the polychalcogenide redox. Such integrated strategy of “dredging and blocking” polychalcogenides in the multi-functional hosts (namely, effective catalysis on the polychalcogenide redox and strong chemisorption of polychalcogenides) will efficiently inhibit the dissolution/shuttle of polychalcogenides. Finally, rational modification of the SEI on Li metal anodes through doping Se or/and Te into the sulfurized SEI in Li-S batteries, will significantly improve the Li+ ionic conductivity of the S-Se-Te chalcogenized organic/inorganic composite SEI and suppress the growth of Li metal dendrites. On the basis of the controllable construction of these promising TexSeySz-based sulfur composite cathodes, stable Li metal anodes and their resultant high-performance Li-S batteries, the corresponding fundamental science will be researched thoroughly. The main research contents are including: the approaches to obtain high sulfur loading, high total capacity, high efficiency and long cycling-life; the roles and contributions of the integrated strategy of “dredging and blocking” polychalcogenides based on defect chemistry of the multi-functional hosts; the novel mechanisms for immobilizing sulfur species based on the high-active and sulfur-rich TexSeySz for high-performance Li-S batteries.