High-entropy metal-organic framework@MXene heterostructure-modified separator promotes polysulfide immobilization and conversion for high-performance lithium-sulfur batteries

HE-MOF@MXene heterostructure was constructed via in situ growth. • The heterostructure combines physical blocking with chemical LiPSs anchoring. • Multi-metal synergy accelerates catalytic conversion of LiPSs. • HE-MOF@MXene//PP delivers 1445 mAh g −1 at 0.2C and 690 mAh g −1 at 5C. • HE-MOF@MXene//PP shows only 0.059% decay per cycle over 900 cycles at 1C. Lithium‑sulfur batteries (LSBs) offer high energy density, yet their performance is restricted by uncontrolled lithium polysulfides (LiPSs) migration and the intrinsically slow multistep conversion of sulfur species. To alleviate these issues, a Fe/Co/Ni/Cu/Mn high-entropy metal-organic framework (HE-MOF) was directly grown on MXene nanosheets to form an HE-MOF@MXene heterostructure, which was subsequently employed as a separator modifier in LSBs. The reciprocal structural regulation between HE-MOF and MXene effectively suppresses component aggregation and layer re-stacking, thereby increasing the accessible surface area of the heterostructure and promoting greater active-site exposure. Meanwhile, the two components are functionally integrated. The well-exposed high-entropy multimetal sites in HE-MOF can effectively exert their adsorption and catalytic advantages toward sulfur species with the assistance of the efficient electron/ion transport network constructed by MXene. Density functional theory calculations suggest distinct electronic structures and d-d interactions among the metal sites in HE-MOF. The resulting multimetal synergy may help accommodate the differentiated adsorption requirements of sulfur species and facilitate their subsequent conversion. Consequently, with the separator functionalized by HE-MOF@MXene, the cell achieves 1445 mAh g −1 at 0.2C. At a high rate of 5C, the cell still delivers 690 mAh g −1 . Moreover, continuous operation over 1000 cycles at 3C results in an average capacity loss of merely 0.060% per cycle. HE-MOF@MXene heterostructure-modified separators integrate efficient physical blocking, strong polysulfide anchoring and rapid sulfur redox reaction kinetics, effectively suppressing shuttle effects and enabling high-performance lithium-sulfur batteries. Download: Download high-res image (239KB) Download: Download full-size image