“蛋黄-蛋壳”结构纳米反应器的设计、调控及在锂硫电池正极中的应用研究

Design,Regulation and Applications in Lithium-sulfur Battery Cathodes of Yolk-shell Nanoreactors

锂硫电池具有理论能量密度高等优势,被认为是最有前景的一类新型二次电池.硫正极存在硫和硫化锂的导电性差、可溶性多硫化物的扩散/穿梭、循环过程中硫的体积膨胀以及氧化还原过程慢等问题,严重制约着电池的活性和循环稳定性.设计“蛋黄-蛋壳”结构纳米反应器应用于锂硫电池正极,可通过调控其“蛋黄”、“蛋壳”和“空腔”结构缓解充放电过程中电极的体积变化,为离子/电子输运提供快速通道,强化对多硫化物的吸附和催化转换作用等,进而提高电极的活性和循环性能,有利于推进锂硫电池的商业化进程.本文总结了“蛋黄-蛋壳”结构纳米反应器的设计和调控策略,包括单核-单壳、单核-多壳、多核-单壳以及多核-多壳等,并结合锂硫电池的工作特点和目前应用存在的问题,对未来发展前景进行了展望.

Lithium-sulfur batteries have attracted much attention due to their high theoretical energy density,which are considered as one of the most promising class of new secondary batteries. In view of the sulfur cathode,there are problems such as the insulation properties of sulfur and lithium sulfide,the diffusion of soluble polysulfides,the volume expansion of sulfur in the cycle process,and the slow dynamics of the redox process,which seriously restricts the activity and cycle stability of the lithium-sulfur battery. Yolk-shell nanoreactors,with easy to regulate“yolk”,“shell”,and“void”,can alleviate the electrode volume in the process of charge and discharge change,provide fast ion/electron transport channel,strengthen polysulfide adsorption and improve catalytic conversion reaction,etc.,thus significantly improve the electrode stability,activity and cycle performance,conducive to promoting the commercialization process in lithium sulfur battery. Thus,we summarize the design and regulation strategy of yolk-shell nanoreactors, including single-yolk-single-shell, single-yolk-multi-shell, multi-yolk-single-shell and multi-yolk-multi-shell. Furthermore,combined with the working characteristics and current application problems of lithium-sulfur battery,the application prospect and future development are also discussed.