高硫含量正极在锂硫电池中的研究进展

Research Progress of Sulfur Cathode with High Sulfur Content for Lithium-Sulfur Batteries

锂硫电池具有高能量密度、原料储量丰富、低成本和环境友好等优点,有望发展为下一代实用化二次电池体系之一。然而锂硫电池中活性物质硫导电性差、多硫化物的溶解与穿梭效应及充放电过程中的体积膨胀等问题阻碍了其商业化进程。通过采用载体材料将硫限域、封装,可以一定程度上解决锂硫电池面临的以上问题。但是传统复合硫正极材料中硫含量和活性物质利用率较低,限制了高能量密度锂硫电池的发展。因此,开发具有高性能和高硫含量的复合硫正极是实现锂硫电池实用化的有效手段。本文从提高复合材料硫含量入手,综述了近年来碳-硫复合材料、过渡金属化合物-硫复合材料和有机硫三种高硫正极材料在锂硫电池中的研究进展,重点讲述了高硫材料的合成方法及其结构对硫和多硫化物的限制与动力学加速作用,并对高硫含量正极材料的未来发展方向进行了展望。

Because of high energy density,abundant storage,low cost and environmental friendliness,lithium-sulfur batteries have been expected as one of the most promising energy storage system.However,the practical application of lithium-sulfur batteries is dramatically hindered by the problems such as poor electro-conductivity of sulfur,dissolution and shuttle effect of polysulfide and volume expansion during charging and discharging process.The above issues can be solved to a certain extent through using sulfur host to limit and encapsulate sulfur.However,the low sulfur content and active material utilization of traditional sulfur-based composite cathodes greatly limit the development of lithium-sulfur batteries with high energy density.Therefore,it is an effective means to exploit the sulfur cathode materials with high performance and high sulfur content for the practical application of lithium-sulfur batteries.Aimed at increasing the sulfur content of sulfur cathodes,this review summarizes the research progress of three kinds of sulfur-based composite materials for lithium-sulfur batteries in recent years,including carbon-sulfur composites,transition metal compounds-sulfur composites and organosulfur.The synthetic methods,chemical structure and their effect on the confinement and kinetics acceleration for sulfur and polysulfide are deeply discussed,and the future development of high sulfur content cathode materials for lithium-sulfur batteries is finally prospected.