Crown Ether-Engineered Porous Liquid-Based Electrolytes Decouple Redox Kinetics and Stability in Zinc-Sulfur Batteries.

Aqueous zinc-sulfur batteries are promising for a new generation of safe and abundant energy storage devices, yet their realization is hindered by sluggish solid-state sulfur redox kinetics at the cathode and parasitic shuttling of iodine mediators in the electrolyte. Here, we demonstrate a path toward resolving these dilemmas by engineering a novel porous liquid-based electrolyte that decouples the essential catalytic activity from deleterious side reactions via microenvironment modulation. The macrocyclic molecular host leverages its intrinsic structural duality-dynamically coordinating a subpopulation of Zn2+ ions to reconstruct their local solvation environment, while utilizing its bulky scaffold to impose steric constraints on polyiodide association and accessibility. This architectural strategy promotes the participation of transient soluble sulfur intermediates and facilitates a more reversible interfacial S↔ZnS conversion, delivering a higher discharge plateau of 0.77 V versus Zn2+/Zn and a reduced cell polarization of 0.38 V at 0.2 A g‒1. Simultaneously, it mitigates mediator-induced zinc corrosion, enabling an 89% capacity retention over 1000 cycles at 1 A g‒1. These findings, based on both experimental and theoretical evidence, elucidate the critical role of steric regulation in electrolyte design, establishing a clear direction for realizing a paradigm shift in aqueous metal-chalcogen batteries.