Ion-Replenishing Interlayer and Tailored Electrolyte Jointly Activate Four-Electron Zinc-Iodine Batteries

Jie Xu; Qingyu Dai; Rui Yang; Yuanhong Yu; Xianyu Song; Donghong Wang; Lei Zhu; Xiangfeng Chu; Yongjie Cao; Yonggang Wang

doi:10.1002/adma.73355

Ion-Replenishing Interlayer and Tailored Electrolyte Jointly Activate Four-Electron Zinc-Iodine Batteries

Adv Mater. 2026 May 9:e73355. doi: 10.1002/adma.73355. Online ahead of print.

Authors

Jie Xu¹, Qingyu Dai¹, Rui Yang¹, Yuanhong Yu², Xianyu Song², Donghong Wang¹, Lei Zhu³, Xiangfeng Chu³, Yongjie Cao⁴, Yonggang Wang⁴

Affiliations

¹ Key Laboratory of Efficient Conversion and Solid-state Storage of Hydrogen & Electricity of Anhui Province, School of Materials Science and Engineering, Anhui University of Technology, Ma'anshan, China.
² Chongqing Key Laboratory of Water Environment Evolution and Pollution Control in Three Gorges Reservoir, School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Wanzhou, China.
³ School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui, China.
⁴ Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, China.

PMID: 42104952
DOI: 10.1002/adma.73355

Abstract

Activating four-electron iodine chemistry in zinc-iodine (Zn-I₂) batteries promises higher energy density, yet remains challenged by polyiodide shuttling and the instability of high-valence I⁺ species. Here, we demonstrate that a customized NH₄Cl-based aqueous electrolyte, coupled with an ion-replenishing Cl-functionalized covalent organic framework (COF-Cl) interlayer, enables long-lived four-electron Zn-I₂ batteries. The optimized electrolyte promotes I⁺-Cl^- complexation, while the COF-Cl interlayer immobilizes polyiodides and continuously releases Cl^- to stabilize I⁺ against hydrolysis, collectively ensuring reversible I^-/I⁰/I⁺ redox conversion. In situ spectroscopic and theoretical analyses reveal accelerated high-valence redox kinetics and strong I⁺/polyiodide interactions. As a result, the optimized cell delivers high energy density (278 Wh kg^- ¹), fast kinetics (128 mAh g^- ¹ at 10 A g^- ¹), and remarkable cycling durability over 45000 cycles at -5°C with an ultralow decay rate of 0.00039% per cycle, with the strategy further validated in pouch cells under low-temperature conditions. This work establishes an effective ion-replenishing interlayer-electrolyte strategy for robust, high-energy aqueous Zn-I₂ batteries.

Keywords: covalent organic frameworks; electrolyte engineering; four‐electron redox reaction; shuttle suppression; zinc–iodine batteries.

Abstract

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