Lewis Acid–Base Interactions Enable Sustained Catalytic Activity for Polysulfide Conversion in Lithium-Sulfur Batteries

en Lithium-sulfur batteries (LSBs) face sluggish sulfur reduction reaction kinetics and severe polysulfide shuttling issues, which significantly limit their performance. In this work, a multifunctional separator with a 3D porous framework featuring confined pore structures and selective adsorption capability is constructed to address these challenges. Within this separator, Lewis acid–base interactions between Ce-MOF-808 and lignosulfonate (SL) effectively regulate the Ce 4+ catalytic activity, thereby lowering the kinetic barrier and accelerating the conversion of short-chain polysulfides into insoluble Li 2 S during the liquid-solid transformation. Furthermore, SL prevents the accumulation of long-chain polysulfides near the Ce 4+ sites through localized electrostatic repulsion, avoiding catalyst poisoning and thereby maintaining continuous catalytic availability. These synergistic effects collectively enable long-lasting catalytic activity toward polysulfide conversion in LSBs, resulting in a fivefold enhancement in capacity and an impressively low capacity decay rate of just 0.033% per cycle over 500 cycles at 1C. This work underscores the transformative potential of Lewis acid–base interactions for enhancing sulfur redox kinetics and introduces a versatile methodology for designing advanced separators for LSBs. 摘要 zh 锂硫电池面临硫还原反应动力学缓慢和严重多硫化物穿梭问题,这显著限制了其性能。在本工作中,我们构建了一种具有受限孔结构和选择性吸附能力的三维多孔框架的多功能隔膜,以应对这些挑战。在该隔膜中,Ce-MOF-808与木质素磺酸盐之间的路易斯酸-碱相互作用有效调控了Ce 4+ 的催化活性,从而降低动力学障碍,加速液-固转化过程中短链多硫化物向不溶性Li 2 S的转化。此外,木质素磺酸钠通过局部静电排斥防止长链多硫化物在Ce 4+ 位点附近积累,从而避免了催化剂中毒,并维持连续的催化可用性。这些协同效应共同促使锂硫电池实现长效的多硫化物转化催化活性,使电池容量提高了五倍,并且在1C条件下经过500个循环后的容量衰减率极低,仅为每循环0.033%。这项工作强调了路易斯酸碱相互作用在增强硫氧化还原动力学方面的变革潜力,并引入了一种用于设计先进锂硫电池隔膜的多功能方法。