Heterointerface Engineering for Stepwise Catalysis of Polysulfides in High Sulfur Loading Lithium‐Sulfur Batteries

ABSTRACT Catalyzing polysulfides conversion is essential for mitigating the shuttle effect and sluggish kinetics in lithium‐sulfur (Li‐S) batteries, yet single‐component catalysts struggle to sustain activity throughout the complex sulfur redox process. Herein, a nanoflower‐structured CoS/Co 9 S 8 heterojunction derived from a MOF template is designed as an advanced sulfur host. The built‐in electric field at the p‐n interface facilitates rapid charge transfer and directional migration of polysulfides, while the distinct catalytic properties of CoS and Co 9 S 8 enable stepwise conversion of lithium polysulfides from S 8 to Li 2 S. Coupled with its hierarchical porous architecture, the host achieves high sulfur loading (84 wt.%) and efficient capture‐diffusion‐conversion of polysulfides. As a result, the assembled Li‐S cell delivers a high discharge capacity of 1295.9 mAh g −1 at 0.2 C, an ultralow decay rate of 0.069% per cycle over 300 cycles at 2 C, and a remarkable volumetric capacity of 1082.07 mAh cm −3 under high sulfur mass loading. This work demonstrates a synergistic morphology and interface engineering strategy to realize high‐energy‐density Li‐S batteries with long‐term stability.