Dual-Site Functional Orchestration Enables Synergistic Anodic Modulation and Cathodic Mooring for Durable Zinc–Iodine Batteries

TL;DR

A new strategy using 2-imidazolidone improves the lifespan and performance of zinc-iodine batteries by stabilizing both the anode and cathode.

Contribution

A dual-site functional molecule is introduced to simultaneously stabilize anode and cathode interfaces in zinc-iodine batteries.

Findings

The carbonyl group modulates Zn2+ solvation to induce (002) deposition and suppress dendrites.

The imino group chemically anchors polyiodides via hydrogen bonding, reducing the shuttle effect.

Symmetric cells lasted over 5500 hours at 8 mA cm-2 with 79.4% capacity retention after 2500 cycles.

Abstract

A dual-site functional orchestration strategy is proposed using 2-imidazolidone to simultaneously reconfigure the anodic solvation structure and suppress the cathodic polyiodide shuttle.The carbonyl (C=O) group modulates Zn2+ solvation to induce preferred (002) deposition, while the imino (N-H) group chemically moors polyiodides via hydrogen bonding, achieving decoupled synergistic regulation.This molecular engineering enables a record-breaking lifespan exceeding 5500 h at 8 mA cm-2 for Zn anodes and durable full-cell cycling with 79.4% capacity retention over 2500 cycles.

A dual-site functional orchestration strategy is proposed using 2-imidazolidone to simultaneously reconfigure the anodic solvation structure and suppress the cathodic polyiodide shuttle.

The carbonyl (C=O) group modulates Zn2+ solvation to induce preferred (002) deposition, while the imino (N-H) group chemically moors polyiodides via hydrogen bonding, achieving decoupled synergistic regulation.

This molecular engineering enables a record-breaking lifespan exceeding 5500 h at 8 mA cm-2 for Zn anodes and durable full-cell cycling with 79.4% capacity retention over 2500 cycles.

The online version contains supplementary material available at 10.1007/s40820-026-02144-5.

Aqueous zinc-iodine batteries represent a compelling technology for large-scale, sustainable energy storage, yet their practical application is severely hampered by the simultaneous interfacial challenges of uncontrolled dendrite growth on the zinc anode and the parasitic polyiodide shuttle. Herein, we introduce a dual-site functional orchestration strategy by employing a single electrolyte additive, 2-imidazolidone (ELA), to concurrently stabilize both the anode and cathode interfaces. On the anode side, the carbonyl (C=O) functional group of ELA initiates an effective anodic modulation, regulating the Zn2+ solvation environment and facilitating a dynamic adsorption layer. This homogenizes the ion flux and guides preferential Zn deposition along the (002) plane, effectively suppressing dendrite formation. Concurrently, at the cathode, the imino (N-H) group immobilizes soluble polyiodide species via hydrogen bonding, realizing an effective cathodic mooring. This targeted confinement arrests the shuttle effect without impeding the intrinsic redox kinetics. This synergistic stabilization translates into exceptional electrochemical performance, with symmetric cells achieving an ultra-long lifespan of over 5500 h at a high current density of 8 mA cm-2 and the full Zn||I2 cells demonstrating robust cycling with 79.4% capacity retention after 2500 cycles. This work introduces a dual-site functional orchestration strategy, offering a pathway toward more durable aqueous batteries.

The online version contains supplementary material available at 10.1007/s40820-026-02144-5.

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