Bimetallic MOF-based separator for suppressing shuttle effects and enabling long cycle life in lithium–sulfur batteries

This disclosure presents a bimetallic metal–organic framework (MOF)-coated separator designed to address the major performance limitations of lithium-sulfur (Li-S) batteries. The separator consists of a Fe-doped ZIF-8 (Fe-ZIF-8) layer deposited on a porous polypropylene substrate, forming microporous (∼10 Å) transport pathways that selectively block polysulfides while permitting uniform Li⁺ transport. The incorporation of Fe sites within the MOF framework provides strong chemical adsorption and catalytic conversion of dissolved polysulfides back into electrochemically active species, thereby suppressing shuttle effects and stabilizing lithium deposition. As a result, Li-S cells employing this separator exhibit enhanced cycling stability, reduced polarization, improved thermal safety, and extended cycle life under practical operating conditions. The separator is fabricated via a low-temperature, aqueous, and scalable process, offering a practical pathway toward commercially viable Li-S battery systems.