A Coordination Supramolecular Network Janus Separator Boost Sulfur Redox Dynamics in Lithium‐Sulfur Batteries

Abstract Lithium‐sulfur (Li‐S) batteries are limited in practical application due to the dissolution and shuttle effect of lithium polysulfides (LiPSs) intermediates. Herein, a multifunctional Janus separator is designed that integrates the zirconium‐based coordination supramolecular network (Zr‐CSN) with the polypropylene (PP) membrane to fabricate Zr‐CSN@PP. The Zr‐CSN@PP constructs a barrier on the side of the sulfur cathode to block the passage of polysulfides, and the nanoporous structure of Zr‐CSN transfers lithium ions quickly. The active zirconium sites and abundant oxygen‐containing groups of Zr‐CSN adsorb and catalyze the polysulfides effectively, which has been proved by experiments and theoretical calculations. Zr‐CSN@PP promotes the migration of Li ⁺ (the lithium‐ion transference number is 0.63) and improves the kinetics of sulfur evolution reactions, enhancing the electrochemical performance of Li‐S batteries. The Li‐S battery with Zr‐CSN@PP separator has a capacity of 650.63 mAh g ⁻¹ after 280 cycles at 0.5 C (average decay of 0.2% per cycle), and a capacity of 422.48 mAh g ⁻¹ after 400 cycles at 2 C. This concept of porous coordination supramolecular networks Janus separator provides a broad prospect for advanced Li‐S batteries.