High‐Performance Lithium‐Sulfur Batteries: Medium‐Entropy Alloys Embedded in CeO ₂ for Polysulfide/Sulfide Bidirectional Catalysis

The slow kinetics of the sulfur reduction reaction (SRR) and Li₂S oxidation reaction (SOR) in lithium-sulfur batteries (LSBs) seriously affect their practical applications. Herein, we prepared a functional interlayer for LSBs consisting of hydroxylated carbon nanotubes dispersed with NiCoMoIr medium-entropy alloys embedded in CeO₂ surface materials. Experimental results revealed a bidirectional catalytic mechanism involving different elements, verifying that Ir and Ni promote the SRR of Li₂S₆ to Li₂S. Meanwhile, Co and Mo were found to primarily promote the conversion process of Li₂S to Li₂S₆. CeO₂ exhibits a bidirectional synergistic effect on enhancing the kinetics of the SRR and SOR. The battery exhibits a specific capacity of 1535.7 mAh g^-1 at 0.2 C, and the decay rate is only 0.051% for per-cycle of 1000 cycles at 1 C. More importantly, a 2 Ah-level pouch cell with an energy density of 436.4 Wh kg^-1 and the capacity decay rate was 0.039% per-cycle after 800 cycles.