锂硫电池隔膜在不同抑制“穿梭效应”策略中的研究进展

Research progress on lithium-sulfur battery separators for different strategies to inhibit the“shuttle effect”

锂硫电池因为具有极高的能量密度和理论比容量,而且作为正极主要材料的单质硫储量丰富、生产成本较低,被认为是未来储能领域中最具应用前景的一类电池。但是在其实际应用之前还有一些技术难题亟待解决,比如活性材料硫的导电性差、正极体积膨胀、穿梭效应等问题严重影响了电池的循环稳定性,尤其是可溶解的长链多硫化物中间体在正极与负极之间来回迁移引起的“穿梭效应”。隔膜作为锂硫电池的关键内层组件,处在正极和负极之间,是抑制多硫化物穿梭的重要屏障,然而目前市场上商用的聚烯烃类隔膜存在较大的孔径,多硫化物容易从中穿过,而且这类隔膜也不具备捕捉多硫化物的能力,因此需要设计具有抑制多硫化物穿梭的功能性隔膜来提升锂硫电池的综合性能。本工作根据多硫化物与隔膜涂层之间的相互作用,将抑制多硫化物穿梭的方法进一步分为物理限制和化学限制,主要介绍了聚丙烯基以及新型纤维素基两类隔膜的研究进展,最后对具有抑制多硫化物穿梭功能的锂硫电池隔膜未来的发展方向进行了展望。

Lithium-sulfur battery is considered the most promising battery in the field of energy storage in the future due to its high energy density and theoretical specific capacity,rich reserves of elemental sulfur as the primary positive material,and low production cost.However,before its practical application,there are still some technical issues to be addressed,such as poor conductivity of the active material sulfur,cathode volume expansion,the shuttle effect,and other issues that seriously affect the battery's cycle stability,especially the“shuttle effect”caused by the migration of soluble long-chain polysulfide intermediates back and forth between the positive and negative electrodes.As the key inner component of the lithium-sulfur battery,the separator is located between the positive and the negative electrodes and is a crucial barrier to preventing the shuttling of polysulfides.However,although it is essential to design a functional separator to prevent the shuttling of polysulfides to enhance the comprehensive performance of lithium-sulfur batteries,the commercial polyolefin separators on the market have a large pore diameter that makes it simple for polysulfides to pass through,and this type of separator cannot capture polysulfides.The approaches to inhibiting polysulfide shuttle are further divided,according to the interaction between polysulfides and the separator coating,into physical restriction and chemical restriction.The research progress of polypropylene-based and new cellulose-based separators is primarily introduced.Finally,the future development direction of lithium-sulfur battery separator with the function of inhibiting polysulfide shuttle is prospected.