Ion Bridging Enables Dual-Interface Engineering for High Capacity and Long Cycling Aqueous Zinc-Sulfur Battery

Aqueous Zn-S batteries (AZSBs) have garnered significant attention owing to their high energy density and low cost. However, their practical application is hindered by the limited electrochemical reversibility of sulfur cathode and the interfacial instability of zinc anode. Here, we developed a functionalized co-solvent electrolyte incorporating aprotic polar tetramethylurea (TMU) and potassium iodide (KI) as synergistic additives, where TMU regulates the Zn²⁺ coordination environment and cooperates with iodide species to construct an electrolyte-derived, interface-confined, and coordination-mediated dynamic ion bridge pathway. This pathway couples TMU-regulated Zn²⁺ transport with I₃ ^-/I^--mediated charge transfer at the sulfur cathode interface, thereby reducing the kinetic barriers for Zn²⁺ transport and ZnS conversion. Meanwhile, the TMU/KI-regulated interfacial environment homogenizes Zn²⁺ flux at the anode, promotes uniform Zn plating/stripping, and suppresses parasitic reactions. Through the synergistic regulation of the ion bridge, the AZSB delivers a high specific capacity of 759 mAh g^-1 at 5 A g^-1 and maintains over 71.2% capacity retention after 1000 cycles. This work proposes a promising electrolyte design strategy for energetic AZSBs via synergistic regulation, offering a promising route toward next-generation sustainable energy storage systems.