Lithium–sulfur batteries (LSBs) are promising energy storage systems, but their practical application is hindered by the polysulfide shuttle effect and slow redox kinetics. To address these challenges, we constructed ZIF-67@CoS_x/MoO₃ with a core–shell structure and CoS_x/MoO₃ with a hollow structure as separator-modified materials for LSBs by varying the degree of sulfidation of ZIF-67. The high intrinsic conductivity of CoS_x facilitated ion transfer between the cathode and separator. Additionally, the introduction of MoO₃ formed a heterogeneous structure with CoS_x that enhanced the adsorption of LiPSs. Via in situ UV-vis and electrochemical impedance spectroscopy testing, we demonstrated the preferred selective trapping and conversion of LiPSs by CoS_x/MoO₃. As a result of the synergistic effect of the bimetallic heterogeneous structure, the modified LSB exhibited excellent cycling stability, with a capacity decay rate of only 0.041% after 500 cycles at 1C. Moreover, it achieved a high discharge capacity of 632 mA h g⁻¹ at 2C. This work provides a novel concept for MOF-derived heterogeneous structures to be applied in high-performance LSBs.

中文翻译：

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MOF 衍生的 Co-Mo 双金属异质结构，用于锂硫电池中多硫化物的选择性捕获和转化


锂硫电池 （LSB） 是很有前途的储能系统，但其实际应用受到多硫化物穿梭效应和缓慢氧化还原动力学的阻碍。为了应对这些挑战，我们通过改变 ZIF-67 的硫化程度，构建了具有核壳结构的 ZIF-67@CoS_x/MoO₃ 和具有中空结构的 CoS_x/MoO₃ 作为 LSB 的隔膜改性材料。CoS_x 的高本征电导率促进了阴极和隔膜之间的离子转移。此外，MoO₃ 的引入与 CoS_x 形成异质结构，增强了 LiP 的吸附。原位通孔紫外-可见分光光和电化学阻抗谱测试，我们证明了 CoS_x/MoO₃ 对 LiPSs 的优选选择性捕获和转换。由于双金属非均相结构的协同作用，改性后的 LSB 表现出优异的循环稳定性，在 1C 下循环 500 次后容量衰减率仅为 0.041%。此外，它在 2C 下实现了 632 mA h ^g-1 的高放电容量。这项工作为 MOF 衍生的非均相结构应用于高性能 LSB 提供了一个新概念。