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 \mathrmI^-/\mathrmI_3^- 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 in-situ solvothermal synthesis process for an entropy-enhanced AgCuZnSnS₄ loaded graphite felt (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 of 88.5% at 20 mA·cm⁻² with 10% state-of-charge. 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.