The application of lithium−sulfur (Li−S) batteries are mainly hindered by the shuttle effect of soluble polysulfides and the sluggish kinetics of sulfur redox reaction. Hence, a bidirectional catalyst, in which single vanadium (V) atoms with V-N₄ coordination and vanadium nitride nanodots with abundant nitrogen vacancies (VN_1-x) are decorated on nitrogen-doped carbon nanosheets (VN_1-x@V-NC), was designed to modify the separators for Li−S batteries. Theoretical calculations and experiments show that V-N₄ and VN_1-x sites display catalytic selectivity for the formation and decomposition of Li₂S, respectively. Additionally, nitrogen-deficient VN_1-x displays a strong affinity toward soluble polysulfides through V-S and Li-N bonds, and polysulfides are preferentially adsorbed near the nitrogen vacancies. Specially, the strong adsorption ability facilitates the subsequent conversion reaction at the dual-site. Consequently, a Li−S battery with VN_1-x@V-NC modified separator based on pure S cathode displays a stable long-term cycling performance over 500 cycles at 2 C. Furthermore, the electrochemical performance of pouch cell with 4 mg cm^-2 S loading demonstrates the potential of the VN_1-x @V-NC modified separator for practical application.

锂硫（Li-S）电池的应用主要受到可溶性多硫化物的穿梭效应和硫氧化还原反应动力学缓慢的阻碍。因此，一种双向催化剂，其中具有 VN ₄配位的单个钒 (V) 原子和具有大量氮空位 (VN _1-x ) 的氮化钒纳米点被装饰在氮掺杂碳纳米片 (VN _1-x @V-NC) 上，旨在修改锂硫电池的隔膜。理论计算和实验表明，VN ₄和VN _{1-x位点分别对Li 2} S的形成和分解表现出催化选择性。此外，缺氮 VN _1-x通过 VS 和 Li-N 键对可溶性多硫化物表现出很强的亲和力，并且多硫化物优先吸附在氮空位附近。特别是，强大的吸附能力有利于后续双位点的转化反应。_{因此，具有基于纯 S 正极的 VN 1-x} @V-NC 改性隔膜的 Li-S 电池在 2 C 下显示了超过 500 次循环的稳定长期循环性能。此外，4 mg cm 的软包电池的电化学性能^-2 S 负载证明了 VN _1-x @V-NC 改性隔膜在实际应用中的潜力。