锂硫电池正极碳纳米孔中固体硫演变过程调控及其对电池性能影响研究

The evolution process of solid sulfur during charge-discharge processes in Li-S batteries will have strong impact on sulfur utilization, which provides one important way to promote the Li-S battery performance. Recently, the investigation of solid sulfur is more about the development of advanced in situ/Operando setups, and monitor the distribution of solid sulfur in the whole electrode during charge-discharge processes. Hindered by the current setups and techniques, the evolution process of solid sulfur within carbon nanopores is still a challenge subject, which needs further study. . On the basis of the applicant’s previous research background, i.e., the in-situ evolution process monitoring of solid sulfur within Li-S cathode materials during charge-discharge processes, the development of in-situ EIS analysis method and their use in Li-S battery mechanism study, in this project, the applicant is going to monitor the solid sulfur evolution process within carbon nanopores through the in situ EIS analysis method. Combining with the ex-situ high resolution imaging and physical sorption techniques which can confirm the sulfur particle size and location, this project can realize the investigation of solid sulfur evolution process within carbon nanopores. Furthermore, through the tune of carbon nanopores on pore nanostructures, chemical compositions and surface properties, the impact of different carbon nanopores on the solid sulfur evolution process is going to be revealed. Subsequently, sulfur particle size and distribution will be controlled by optimized carbon nanopores, which will enhance the sulfur utilization and promote the Li-S battery performance in the end. This project will build the relationship between the physicochemical properties of carbon nanopores and the sulfur utilization, which will shed light on the cathode materials design and Li-S battery performance promotion.

锂硫电池充放电过程中固体硫的演变过程会对硫的利用率产生重要影响，是提升电池性能的关键因素之一。目前对固体硫的研究集中在制备先进原位装置，表征和监测固体硫在多孔碳材料中的宏观分布。受仪器和技术限制，微观碳纳米孔内固体硫演变行为的认识和调控是一个有挑战性的课题，有待深入研究。.基于申请人前期原位监测锂硫电池正极中固体硫演变过程研究和阻抗谱解析应用等基础，本项目将通过原位阻抗谱解析法监测固体硫演变过程，结合非原位高分辨成像技术和物理吸附测试，表征固体硫在碳纳米孔中的粒径和分布，研究碳纳米孔中固体硫演变行为。深入认识碳纳米孔结构、组成和表面性质对固体硫演变过程的影响，调控不同碳纳米孔中固体硫演变过程，控制硫粒径及分布，高效限域其于碳纳米孔内，最终提高硫利用率，提升电池性能。本项目将构建碳纳米孔物化性质与硫利用率的构效关系，对锂硫电池正极材料设计和提升锂硫电池性能具有重要指导意义。

锂硫电池充放电过程中固体硫的演变过程会对硫的利用率产生重要影响，是提升电池性能的关键因素之一。目前对固体硫的研究集中在制备先进原位装置，表征和监测固体硫在多孔碳 材料中的宏观分布。受仪器和技术限制，微观碳纳米孔内固体硫演变行为的认识和调控是一个 有挑战性的课题，有待深入研究。 .本项目制备了具有不同孔结构、组成、表面性质的碳材料和碳/金属硫化物复合材料，结构上包括：空心、核壳、双层结构和蛋黄-蛋壳结构，组成上包括：N掺杂和单/双金属硫化物复合等；以酚醛树脂为碳前驱体，掌握了具有不同结构、组成、表面性质的碳纳米孔材料及其复合材料的制备方法和结构演变规律；采用阻抗谱，结合高分辨成像技术和物理吸附测试等表征手段对材料和电极进行了表征，表征结果与锂硫电池性能关联，研究发现，材料具有空心结构时，壳壁的厚度和可穿透性对锂硫电池性能有重要影响，壳壁较薄、具有穿透性的材料性能较高；对不同结构、组成、表面性质碳纳米孔中固体硫的演变过程进行了研究，深入理解碳纳米孔结构、组成、表面性质在固体硫演变过程中的作用。本项目对锂硫电池正极材料设计和提升锂硫电池性能具有重要指导意义。