锂硫电池柔性正极材料研究进展

随着化石能源的日渐枯竭、能源危机和环境问题的日益突出,开发环境友好的二次电池能源体系迫在眉睫。锂硫电池作为一种新型的储能电池,其理论比容量高达1 675 mAh/g,质量密度可达2 600 Wh/kg,且原材料来源广、成本低等优点,使得其有望代替锂离子电池成为下一代理想的能源电池。近年来,可穿戴电子设备、智能纺织品的出现,对储能电池提出了更高的要求-柔性,因此开发柔性锂硫电池已经成为研究热点。作为锂硫电池的重要组成部分,柔性正极材料的研究和制备对柔性锂硫电池系统的开发至关重要。从锂硫电池柔性正极基体材料入手,对碳材料、导电聚合物材料和新兴的MOF材料等3个方面进行了分类总结,详细阐述了各自制备方法及对柔性正极性能影响。碳材料高的导电性和多孔结构设计、导电聚合物和MOF材料对多硫化物优异的化学吸附作用,均有助于抑制多硫化物的"穿梭效应",提升柔性锂硫电池的长循环电化学稳定性能。最后分析了现有锂硫电池柔性正极材料存在的缺陷与问题,对未来发展方向做出了展望。这将为开发新型的锂硫电池用柔性正极材料提供指导,同时为其它二次电池柔性正极材料开发过程中的共性问题提供实验和理论依据。

Research progress on flexible cathode materials for lithium-sulfur batteries

With the increasingly prominent of depletion of fossil energy, energy crisis and environmental problems the development of an environmentally-friendly secondary battery energy system is hanging over one’s head. As a new type of energy storage battery, lithium-sulfur battery has a high theoretical specific capacity and energy density, and the advantages of wide source of raw materials, low cost, etc. All of these merits are expected to replace lithium-ion batteries as the next-generation ideal energy battery. In recent years, the emergence of wearable electronic devices and smart textiles has put forward a higher requirement for energy storage batteries-flexibility, so flexible lithium-sulfur batteries have become a research hotspot. As an important part of the lithium sulfur battery, the study and prepration of flexible cathode materials are crucial for the fast development of flexible lithium-sulfur batteries and their system. In this paper, the flexible cathode matrix material for lithium-sulfur batteries is introduced, and classifies and summarizes the three aspects of various carbon materials, conductive polymer materials and emerging MOF materials. The preparation methods and their effects on the electrochemical performance of flexible cathode are described in detail. The high conductivity and porous structure design of the carbon materials, the excellent chemisorption of the polysulfide by the conductive polymer and the MOF material all contribute to the inhibition of the "shuttle effect" of the polysulfide during charge and discharge process and improve the electrochemical stability of the flexible lithium sulfur battery during long cycle process. Finally, the defects and problems of the existing flexible cathode materials for lithium-sulfur batteries are analyzed, and the future development direction is prospected. This will provide guidance for the development of new flexible cathode materials for lithium sulfur batteries, and provide experimental and theoretical basis for the common problems in the development of other flexible cathode materials for other secondary batteries.