In lithium–sulfur batteries (LSBs), soluble long-chain polysulfide intermediates can easily shuttle between the cathode and the anode, causing rapid performance degradation. Although significant progress, through rational cathode structure and composition design, has been made to solve the polysulfide shuttling problem, this challenging issue still exists. Considering the function of a separator in a cell is to isolate the cathode and anode materials, the transport properties of species across the separator should be investigated. Using bacterial cellulose (BC) as an example of a functional separator, we hypothesize that grafting anionic function groups on the cellulose chains could create an energy barrier that will block the diffusion of polysulfides across the separator. In our study, BC is functionalized by oxidizing hydroxyl groups on cellulose chains into carboxylate groups. Physicochemical and electrochemical studies confirm polysulfide shuttling is effectively suppressed. As a result, functionalized BC separator equipped LSB cells with a sulfur load of 4 mg/cm² delivers ~1,300 mAh/g of specific capacity at 0.1°C, which can be maintained after 100 cycles above 1,000 mAh/g at 0.3°C, demonstrating its superior performance over commercial polyolefin-based separators.

在锂硫电池（LSB）中，可溶性长链多硫化物中间体很容易在正极和负极之间穿梭，导致性能迅速下降。尽管通过合理的正极结构和成分设计，在解决多硫化物穿梭问题方面取得了重大进展，但这一具有挑战性的问题仍然存在。考虑到电池中隔板的功能是隔离阴极和阳极材料，应研究物质穿过隔板的传输特性。使用细菌纤维素 (BC) 作为功能隔板的例子，我们假设在纤维素链上接枝阴离子官能团可以产生能量屏障，阻止多硫化物穿过隔板的扩散。在我们的研究中，BC 通过将纤维素链上的羟基氧化成羧酸根而被官能化。物理化学和电化学研究证实多硫化物穿梭被有效抑制。结果，功能化的 BC 分离器配备了硫负载为 4 mg/cm2 的 LSB 电池²在 0.1°C 下提供~1,300 mAh/g 的比容量，在 0.3°C 下循环 100 次后可保持在 1,000 mAh/g 以上，证明其性能优于商用聚烯烃基隔膜。