Enhancing Sulfur Redox Kinetics of Carbon‐Supported Cobalt Diselenide Electrocatalysts via an Anion‐Doping Strategy

The growing demand for high‐energy‐density rechargeable batteries has stimulated extensive interest in lithium–sulfur (Li–S) systems, but their practical application remains severely hindered by sluggish sulfur redox kinetics and the shuttle effect of lithium polysulfides (LiPSs). Herein, an anion S‐doping strategy is presented to synthesize carbon‐supported cobalt diselenide (CoSe 2− x S x ) electrocatalysts using ZIF‐67 as the precursor via a one‐step pyrolysis process. Experimental results and characterization analysis reveal that the S incorporation into CoSe 2 not only enhances structure stability, but also modulates the electronic structure of electrocatalytic sites by increasing the proportion of high‐valence cobalt species, thereby strengthening the chemical anchoring of LiPSs and accelerating their redox conversion kinetics. As a result, the optimized CoSeS exhibits superior electrocatalytic performance, where the CoSeS/S cathode delivers a high specific capacity of 1169 mAh g −1 at 0.1 C and 75.6% of its capacity after 500 cycles at 1 C, with a capacity decay of only 0.05% per cycle. Even at a high sulfur loading of 5.81 mg cm −2 , it still achieves a reversible areal capacity of 4.7 mAh cm −2 after 60 cycles at 0.2 C. This work provides an effective anion‐doping means to tailor the structure and electrocatalytic activity of host materials for Li–S batteries.