<scp> RuO ₂ </scp> ‐Based High‐Entropy Oxide and Its Asymmetric Catalysis on Polysulfide Conversion in Lithium–Sulfur Batteries

High‐entropy oxides with five or more metal components in a single oxide phase, hold attractive potential to enhance the lithium polysulfides adsorption–catalysis ability in Li‐S batteries due to the noteworthy synergistic effect of the multiple metal sites. Herein, we have synthesized an RuO 2 ‐based high‐entropy oxide, that is, (RuIrFeCoNi)O 2 via a simple molten salt method for Li‐S batteries. Our results prove that the introduction of multiple metal components endows high‐entropy oxide with moderate adsorption of lithium polysulfides and promising bidirectional catalysis on the liquid–solid conversion between soluble lithium polysulfides and insoluble Li 2 S. Particularly, compared with the quaternary (RuFeCoNi)O 2 catalyst, the inferior kinetics enhancement of the lithium polysulfides generation, but the superior promotion of Li 2 S deposition for high‐entropy oxide greatly favors the inhibition of shuttle effect. Such an asymmetric catalysis behavior induces remarkable electrochemical performance of Li‐S batteries assembled with high‐entropy oxide‐modified separator. High specific capacities of 1641.1 mAh g −1 at 0.1 C and 812.5 mAh g −1 at 2 C are achieved. Remarkably, superior cycle stability is realized with a low capacity decay rate of only 0.060% per cycle within 1000 cycles at 1 C rate. This study unveils the catalytic mechanism of high‐entropy oxide in promoting polysulfide conversion and offers a robust foundation for designing efficient catalysts for Li‐S batteries.