A Sustainable Multipurpose Separator Directed Against the Shuttle Effect of Polysulfides for High‐Performance Lithium–Sulfur Batteries

Abstract The success of lithium–sulfur batteries will reduce the expected Co, Ni resource challenges from the wide adoption of lithium‐ion batteries. Unfortunately, the shuttle effect of soluble polysulfides brings many problems. Anchoring or blocking polysulfides on the cathode side using functional separators is the dominant strategy for addressing this. However, the blocked polysulfides gradually aggregate on the separator to form the so‐called “dead sulfur” and withdraw from cycling. Herein, a multipurpose separator is proposed that enables catalytic activation of the blocked polysulfides to prevent the formation of “dead sulfur”, and contribute to capacity. The multifunctionality is supported by montmorillonite (MMT) that provides sufficient channels for lithium‐ion transport, and selenium‐doped sulfurized‐polyacrylonitrile (Se 0.06 SPAN) that catalyzes conversion of “dead sulfur” and simultaneously contributes capacity. The theoretical calculations reveal Se 0.06 SPAN/MMT has a low migration barrier for Li + and a low decomposition barrier for Li 2 S, facilitating the conversion and minimizing “dead sulfur”. Consequently, the Li–S battery with the Se 0.06 SPAN/MMT@PP (polypropylene) separator shows a low fading rate of 0.034% during 1000 cycles and achieves a super‐high areal capacity (33.07 mAh cm –2 ) under high sulfur loading (26.75 mg cm –2 ) and lean electrolyte conditions (4.5 µL mg –1 ). Moreover, the multipurpose separator has encouraging performance in stability, flexibility, and sustainability.