新型多孔碳-二硫化硒纳米复合材料的可控制备与储锂机制

The development of high-performance, low-cost lithium-selenium sulfide (Li-SexSy) batteries is an emerging research frontier in energy storage and nanotechnology. Current Li-SexSy batteries suffer from rapid capacity decay which is caused by multiple mechanisms, e.g. low conductivity, polyselenides/polysulfides dissolution, and large volume expansion during lithiation. This project aims to tackle the key challenges of Li-SexSy batteries. Novel porous carbon materials will be designed for SeS2 hosting to enhance its conductivity, suppress its dissolution in the electrolyte, and accommodate its volume expansion. Specifically, the sol-gel method and spray drying method will be utilised to prepare novel porous carbon materials with ultra-high pore volume, tailored structure and surface chemistry. Different amounts of SeS2 will be loaded into the porous carbon matrix. The effects of structure, pore size, surface chemistry, and SeS2 loading amount on the electrochemical performances will be systematically studied. The fundamental understanding on structure-electrochemical performance correlation generated from this study will advance the development of Li-SexSy batteries.

高性能、低成本锂硫化硒电池的开发是新能源技术和纳米技术的交叉和前沿。针对现有锂硫化硒电池导电性低、活性物质易溶出以及嵌锂过程中的体积膨胀等问题，本项目拟设计新型多孔碳材料负载活性客体二硫化硒，提高二硫化硒的导电性，抑制活性组分溶出，缓解材料的体积膨胀，从而提高锂硫化硒电池的电化学性能。通过溶胶-凝胶法和喷雾干燥法制备新型的、具有超大孔容的、微观结构和表面功能化可控的多孔碳材料，并以此为载体填充不同含量的电化学活性客体二硫化硒；系统研究多孔碳材料的结构、孔径大小、表面功能化、二硫化硒负载量等结构参数对锂硫化硒电池电化学性能的影响，探索材料结构与物性之间的内在联系，为新型锂硫化硒电池的研发奠定科学基础。

高性能、低成本锂-硫化硒电池的开发是新能源技术和纳米技术的交叉和前沿。针对现有锂-硫化硒电池导电性低、活性物质易溶出以及嵌锂过程中体积膨胀大等问题，本项目设计构筑了一系列高孔容、高比表面积多孔碳材料用于负载活性客体二硫化硒，提高了二硫化硒的导电性，抑制了活性组分（多硫离子、多硒离子）的溶出，缓解了二硫化硒锂化过程中的体积膨胀，实现了锂-硫化硒电池电化学性能的大幅提升。例如，我们设计了一种双层空心碳球用于二硫化硒负载。所获得的复合材料中二硫化硒的负载量高达75 wt.%。该二硫化硒/双层空心碳球复合材料在200 mA/g电流密度下具有高达930 mAh/g的比容量，循环100圈后，容量保持在910 mAh/g。在1000 mA/g电流密度下循环900圈后，容量保持率高达89%。该材料在新型锂-硫化硒电池中呈现出良好的应用前景。此外，我们还构筑了一系列硫/碳复合材料、金属硫化物、金属硒化物和氧化硅基材料。这些材料在锂-硫电池、锂离子电池等方面都具有一定的应用前景。