Decoupling of Ion‐Solvent Interactions via Compartmentalized Molecular Design for Ultra‐Stable Aqueous Zinc Batteries

Abstract The ubiquitous challenge of reconciling thermodynamic stability with kinetic efficiency in solvated ion transport limits the performance of zinc metal batteries. Here, a design principle is presented inspired by biological ion channels, compartmentalized molecular interactions that spatially decouple ion coordination from bulk solvent dynamics. Through dimethyl hydroxymethylphosphonate (DHP), a bipolar co‐solvent featuring weakly coordinating phosphonate and hydrogen‐bonding hydroxyl groups, that simultaneous control over localized dehydration and global electrolyte stability is demonstrated. The phosphonate group selectively displaces primary solvation water via low‐affinity Zn ²⁺ coordination, while hydroxyl moieties reconstruct hydrogen‐bond networks to immobilize solvation water, which elevates the water dissociation energy barrier and slashes hydrogen evolution. Experimental and theoretical results reveal that the compartmentalized design of DHP mimics biological ion channels, where directional interactions guide rapid Zn ²⁺ desolvation while suppressing electron transfer to water. The optimized electrolyte enables Zn─Zn symmetric cells to achieve exceptional stability (4500 h at 5 mA cm ⁻² ) and a Coulombic efficiency of 99.81% over 1950 cycles. When paired with NH ₄ V ₄ O ₁₀ cathodes, full cells retain 77.8% capacity after 8500 cycles at 3 A g ⁻¹ , setting a new benchmark for aqueous zinc batteries.