Synergizing ZIF-67 activity with polyetherimide to achieve dendrite and shuttle-free lithium sulfur batteries

Lithium-sulfur (Li[sbnd]S) batteries promise environmental compatibility and high energy density but are constrained by the various challenges related to polysulfide shuttling, sluggish sulfur kinetics, and dendritic corrosion. Metal-organic frameworks (MOFs) emerge as leading catalytic materials to address these bottlenecks in the practical utility of Li[sbnd]S batteries through their robust induction in the cost-effective designs of multifunctional separators. Herein, a rational dodecahedron ZIF-67 nanostructured pore morphology was synergistically combined with polyetherimide (PEI) to design a functional separator (PEI@ZIF-67) through a simplified phase inversion method. The theoretical and experimental findings reveal that the proposed synergism holds an excellent trapping efficiency towards the polysulfides while facilitating the homogeneous transportation of Li⁺ ions across the electrodes. Consequently, the PEI@ZIF-67 manifests the highest blockage towards dendritic growth even at high current densities in symmetric cells and respective sluggish sulfur kinetics in Li[sbnd]S batteries. Leveraging these multiple stabilization features, the PEI@ZIF-67 based Li[sbnd]S batteries offer excellent cycling (retained capacity 922 mAh g⁻¹ @0.2C-200, 839 mAh g⁻¹ @1C-250, and 714 mAh g⁻¹@2C-300 cycles) and rate performance at various current densities. Furthermore, the proposed design actively tolerates high sulfur loading of 7.3 mg cm⁻² by delivering a promising specific capacity of 547 mAh g⁻¹ after 50 stable cycles. This study is expected to open new potential for synergism of active catalytic materials with novel polymers to advance the prospects of high energy density Li[sbnd]S batteries.