Engineering a light-weight, thin and dual-functional interlayer as “polysulfides sieve” capable of synergistic adsorption for high-performance lithium-sulfur batteries

The modification of commercial separator, as one of the most promising methods to alleviate the “shuttle effect” of lithium polysulfides for high-performance lithium-sulfur batteries (LSBs), has rarely employed well-dispersed non-bulk materials with well-defined nanostructures to fabricate modified interlayer from the previous reports. Herein, adopting ZIF-8@ZIF-67 core-shell nanocrystals derived double-shelled hollow N-doped porous carbon polyhedrons (DS_xHNC) as the main component, ketjen black (KB) as the conductive modifier and structural filler, and hydrogen as the shell tailor, a potent polysulfides barrier is developed to inhibit LiPSs shuttling by forming light-weight, thin and dual-functional interlayer onto commercialized polypropylene separator (PPS) via simple doctor blade coating with negative-pressure infiltration. This method well addresses the uneven accumulation and easy exfoliation of DS_xHNC, and simultaneously optimizes the densification of interlayer. Owing to the physically/chemically synergistic adsorption toward LiPSs, the cell using DS₁₄₅HNC/KB@PPS with an interlayer of 8.43 μm (thickness) and 0.4864 mg cm⁻² (mass loading) delivers prominent cycling life with a capacity degradation of 0.067% per cycle (500 cycles) at 1 C based on low sulfur content (1.0 mg cm⁻²) cathode and a high capacity retention of 80% (100 cycles) at 0.2 C based on high sulfur content (3.1 mg cm⁻²) cathode, separately. This work shares a novel strategy for the synthesis of light-weight, thin and dual-functional interlayer onto PPS for high-performance LSBs.