Tailoring MOF Separator with Enhanced Lithium‐Ion Desolvation for High Sulfur Redox Kinetics in Lithium–Sulfur Batteries

ABSTRACT Ideal separators for rechargeable lithium–sulfur (Li–S) batteries should facilitate Faradaic reactions near the electrode surface while mitigating the shuttle effect. However, conventional separator materials often exhibit sluggish Li + migration rates and reaction kinetics due to their high Li + desolvation energy and diffusion resistance. Investigating the Li + transport mechanism within separators and elucidating Li + desolvation process remains a significant challenge. Herein, we systematically elucidated the desolvation capability of Metal–organic frameworks (MOF) channels in Li + diffusion process by MOF pore engineering. It is concluded that negative charge sites weaken the interaction between Li + and solvent molecules, and smaller pore sizes reduce the distance between Li‐solvent complexes and negatively charged sites, which further improve the desolvation of Li + . The desolvated Li + subsequently participates rapidly in the polysulfide conversion process, thereby enhancing sulfur redox kinetics and keeping the concentration of polysulfides in the electrolyte remains at a lower level. This enables Li–S batteries to exhibit excellent electrochemical performance under high current densities and high sulfur contents. This work provides valuable new insights into controlling the Li + solvation structure, highlight the significant potential of MOF‐based separators in Li–S batteries.