Boosting Polysulfide Conversion Reactions via Constructing RuCo Alloy Catalysts in Li-S Batteries

The shuttle effect of intermediate lithium polysulfides (LiPSs) and sluggish redox kinetics limit the practical application of lithium-sulfur (Li-S) batteries. Herein, RuCo alloy nanoparticles supported on N-doped mesoporous carbon spheres (RuCo/NMCS) are developed as efficient catalytic sulfur hosts. Electron transfer from Co to Ru optimizes the adsorption and catalytic conversion of LiPSs, accelerating sulfur redox reactions. Meanwhile, the dynamic changes of Ru and Co species in the RuCo/NMCS electrode demonstrate the strong Ru-S and Co-S interactions between metals and LiPSs during the discharge-charge process, corresponding to the accelerated conversions of Li₂S₂/Li₂S to LiPSs and LiPSs to S₈. Consequently, the RuCo/NMCS electrode showcases improved electrochemical performance with enhanced cycling capacity and stable reversible capacity. This work provides a feasible and rational route to construct alloy electrocatalyst-supported cathode materials with bidirectional catalysis on LiPS conversion, promoting the application of alloy electrocatalysts as kinetic regulators for high-performance Li-S batteries.