Sb2S3量子点的可控制备及电化学储钾性能研究

Sb2S3 with a high theoretical specific capacity of 967 mAh/g is a promising anode material for potassium-ion batteries (PIBs), however, the large volume expansion and sluggish ions diffusion rate during the charge-discharge process would lead to poor cycle performance and rate capability. In view of the abundant active sites, easy stress relaxation and short ion diffusion distance of quantum dot (QD), in this project, Sb2S3 QD and its carbon composites will be prepared, the effects of size, confinement and buffering of heterogeneity are employed to overcome the volume expansion, shorten the ion transport path and enhance the electrode conductivity, thus improving the electrochemical potassium storage performances of Sb2S3. The controllable preparation and formation mechanism of Sb2S3 QD and its carbon composites will be systematically explored. The relationship between size, composite ways (single-particle coating, multi-particles embedding and multi-particles loading), interface action forms (physical absorption and chemical bonding) and electrochemical potassium storage performances is planned to be established, constructing the high-performance Sb2S3-based anode materials for PIBs. The capacitance/diffusion-controlled kinetics process and electrochemical potassium storage mechanism are going to be analyzed. Finally, the effective theoretical support for Sb2S3 anode materials of PIBs can be provided.

Sb2S3材料的理论储钾比容量高达967mAh/g，是十分有前景的钾离子电池负极材料，但其在充放电过程中存在体积膨胀大、离子扩散速率慢等问题，致使其循环稳定性差、倍率性能不足。鉴于量子点材料具有活性位点丰富、应力松弛容易、离子扩散距离短等特点，本项目拟构筑Sb2S3量子点及其碳复合材料，通过尺寸效应、限域效应及异质缓冲效应克服体积膨胀、缩短离子传输路径、增强电极电子导电性，从而提升Sb2S3材料的电化学储钾性能。系统研究Sb2S3量子点及其碳复合材料的可控制备及形成机制，建立Sb2S3量子点及其复合材料的尺寸、复合方式（单颗粒包覆、多颗粒包埋、多颗粒负载）、界面作用（物理吸附、化学键合）与储钾性能间的构效关系，构建高性能钾离子电池Sb2S3基负极材料；解析电极材料电容/扩散控制的动力学过程，阐明其电化学储钾机制，为钾离子电池Sb2S3负极材料的研究提供理论支撑。

本项目主要针对锑基材料在作为钾离子电池负极材料时，在充放电过程中存在体积膨胀大、离子扩散速率慢等问题开展了系统研究。设计制备了系列碳/锑基复合材料，通过尺寸效应、限域效应及异质缓冲效应克服体积膨胀、缩短离子传输路径、增强电极电子导电性，从而有效提升了锑基材料的电化学储钾解析了电极材料电容/扩散控制的动力学过程，阐明其电化学储钾机制，为钾离子电池锑基负极材料的研究提供了理论支撑。在完成项目的主要内容之外，还在本项目内容的基础上进行了一定的拓展，以碳点为前驱体构建了杂原子掺杂的碳纤维材料，并系统研究了其电化学储钾性能；通过构筑多维碳/Sb2S3复合材料，阐明了Sb2S3与碳材料的界面结构与电化学储锂性能之间的内在联系；制备了包埋于碳基体中的锑量子点复合材料，揭示了锑量子点尺寸效应及界面化学键对储钠性能的影响。最终，通过本项目的研究，为开发高性能碱金属离子电池碳/锑基负极材料提供了一定的理论技术支持。

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