Harnessing High Entropy Sulfide (HES) as a Robust Electrocatalyst for Long-Term Cycling of Lithium-Sulfur Batteries

The pursuit of highly efficient electrocatalysts is of utmost significance in the relentless drive to enhance the electrochemical performance of lithium-sulfur batteries. These electrocatalysts enable a predominant contribution (~75%) to the overall discharge capacity during cycling by facilitating the rapid conversion of long-chain lithium polysulfides into insoluble short-chain products (Li₂S₂ and Li₂S). Herein, high entropy sulfides derived from high entropy metal glycerate templates are synthesized and utilized as electrocatalysts. Among the evaluated materials, high entropy sulfides containing Ni, Co, Fe, Mg, and Ti (GS-3) showcases modulated spherical morphology, uniform elemental distribution, and efficient catalytic properties, outperforming high entropy sulfides containing Ni, Co, Fe, Mg, and Zn (GS-1) and high entropy sulfides containing Ni, Co, Cu, Mg, and Zn (GS-2). Consequently, a typical lithium-sulfur battery incorporating the GS-3/S/KB cathode (S loading ~2.3 mg cm⁻²) demonstrates a high initial discharge capacity of ~1061 mAh g⁻¹ at 0.5 C and stable cycling (1500 cycles) at the lowest capacity decay rate of 0.032% per cycle. The results are superior to the electrochemical performance of GS-1/S/KB (~945 mAh g⁻¹, 0.034%), GS-2/S/KB (~909 mAh g⁻¹, 0.086%), and S/KB (~748 mAh g⁻¹, 0.19%) cells. This work highlights the incorporation of titanium and other metal elements into the sulfide structure, forming high entropy sulfides (i.e., GS-3) that facilitates efficient catalytic conversion and enhances the cycling performance of lithium-sulfur batteries.