High-Entropy Sulfides Catalyze Rate-Determining Redox in Fast-Charging Aqueous Zinc-Sulfur Batteries

The sluggish kinetics of the solid-solid Zn-S redox process significantly hinders the practical energy density and lifespan of fast-charging aqueous Zn-S batteries (AZSBs). Conventional low-entropy catalysts suffer from poor stability, leading to leaching effects and water splitting during cycling. To overcome these limitations, we present a three-step synthesis of high-entropy sulfide (HES) nanorod catalysts to accelerate the rate-determining step (RDS) in the Zn-S redox process. Operando synchrotron powder diffraction, operando synchrotron infrared reflectance microscopy, and operando Raman spectroscopy characterizations reveal that the HES catalysts improve sulfur utilization by accelerating the RDS conversion of ZnS₂ to wurtzite ZnS. Furthermore, near-edge X-ray absorption fine structure and inductively coupled plasma mass spectrometry analyses demonstrate that the HES catalysts effectively suppress the leaching effect of transition metals and water splitting of the aqueous electrolyte, improving cycling stability. In contrast, utilizing medium- and low-entropy catalysts results in the formation of by-products, including S₅ ^2-, S₃ ^2-, and SO₃ ^2- species. Consequently, the pouch cell with the HES catalysts delivers a high cathode energy density of 313 Wh kg^-1 and high cycling stability over 400 cycles at 4 C with 0.06% capacity decay per cycle. This entropy-driven catalytic strategy provides an effective approach for developing stable and fast-charging aqueous metal-sulfur batteries.