Enriched Selenium Vacancies Modulating Ru─CoSe_V as Polysulfide Conversion Reaction Accelerator in Lithium–Sulfur Batteries

Lithium–sulfur (Li─S) batteries have been widely regarded as promising candidates for next generation energy storage technologies due to their cost-effectiveness and high theoretical energy density. However, their commercialization faces challenges such as volume expansion, lithium polysulfides （LiPSs） shuttling, and slow sulfur redox kinetics. Herein, a porous catalytic reactor (Ru─CoSe_V) is rationally designed through the enriched Se vacancies modulated metal-substrate interaction. The Se vacancies adjust the intrinsic electronic environment around the vacancies, act as a reservoir for Ru cluster loading, and contribute to the strong interactions between CoSe_V and Ru cluster. Furthermore, the porous architecture of the prepared catalyst facilitates rapid charge and ion transfer while ensuring the efficient exposure of catalytic sites. Electrochemical tests combined with theoretical calculations revealed that the Ru─CoSe_V can provide both strong catalytic activity and adsorption capacity for LiPSs. As a result, the assembled Ru─CoSe_V/S electrodes demonstrated excellent performance in terms of capacity enhancement and cycling stability, achieving high initial discharge capacity of 1321.1 mAh g⁻¹ at 0.2 C and low capacity decay rate of 0.031% per cycle at 1 C over 500 long-term cyclings, and reaching a high areal specific capacity (7.1 mAh cm⁻²) at sulfur loading of 7.5 mg cm⁻².