Orbital Hybridization-Engineered Electronic Structure in Multicomponent Sulfides Boosts the Performance of Polysulfide/Iodide Flow Batteries

Despite their attractive features of high energy density, low cost, and safety, polysulfide/iodide flow batteries (SIFBs) are hampered by the sluggish kinetics of the iodide redox couple, which restricts overall performance. Multicomponent sulfides are demonstrated as promising catalysts for accelerating I^-/I₃^- redox reactions. Concurrently, the enhanced configurational entropy arising from multinary compositions drives synergistic effects among constituent elements, establishing a viable pathway to optimize catalytic performance. Building on these foundations, this work introduces a targeted orbital hybridization-optimized electron density strategy to enhance the catalytic activity. Implementing this concept, we developed an <i>in-situ</i> solvothermal synthesis process for an entropy-enhanced ACZTS/GF electrode. The engineered electrode demonstrates exceptional electrocatalytic performance with improved bulk conductivity and interfacial charge transfer kinetics within a SIFB. The cell achieves a high energy efficiency (EE) of 88.5% at 20 mA cm^-2 with 10% SOC. Furthermore, the battery delivers a maximum power density of 119.8 mW cm^-2 and exhibits excellent long-term cycling stability. These significant results stem from orbital hybridization-driven electronic state optimization and entropy effect-induced synergistic catalysis.