Suppressing\nthe Shuttle Effect and Dendrite Growth\nin Lithium–Sulfur Batteries

Abstract

Practical\napplications of lithium–sulfur batteries are simultaneously\nhindered by two serious problems occurring separately in both electrodes,\nnamely, the shuttle effects of lithium polysulfides and the uncontrollable\ngrowth of lithium dendrites. Herein, to explore a facile integrated\napproach to tackle both problems as well as guarantee the efficient\ncharge transfer, we used two-dimension hexagonal VS₂ flakes\nas the building blocks to assemble nanotowers on the separators, forming\na symmetrical double-side-modified polypropylene separator without\nblocking the membrane pores. Benefiting from the “sulfiphilic”\nand “lithiophilic” properties, high interfacial electronic\nconductivity, and the unique hexagonal tower-form nanostructure, the\nD-HVS@PP separator not only guarantees the effective suppression of\nthe lithium polysulfide shuttle and the rapid ion/electron transfer\nbut also realizes uniform and stable lithium nucleation and growth\nduring cycling. Hence, just at the expense of an 11% increase in the\nseparator weight (0.14 mg cm^–2), the D-HVS@PP separator\ndelivers an over 16 times higher initial areal capacity (8.3 mAh cm^–2) than a conventional PP separator (0.5 mAh cm^–2) under high sulfur-loading conditions (9.24 mg cm^–2). Even when used under a low electrolyte/sulfur ratio\nof 4 mL g^–1 and a practically relevant N/P ratio\nof 1.7, the D-HVS@PP separator still enabled stable cycling with a\nhigh cell-level gravimetric energy density. The potentials in broader\napplications (Li–S pouch battery and Li–LiFePO₄ battery) and the promising commercial prospect (large-scale production\nand recyclability) of the developed separator are also demonstrated.