Phase Inversion-Engineered Ultrathick Electrodes With Intrinsic Hydrogel Interphase for High Areal Capacity Aqueous Zinc-Iodine Batteries at Room/Subzero Temperatures.

Authors

Fanxiang Meng, Peiyao Wang, Zeheng Lv, Huadong Jiang, Qilong Wu, Minghao Zhang, Wenhao Yang, Xue Li, Cheng Chao Li, Yang Yang

Published in

Advanced materials (Deerfield Beach, Fla.). Pages e74986. Sep 15, 2026. Epub Sep 15, 2026.

Abstract

Thick cathodes are essential to maximize the practical energy density of zinc-iodine (Zn-I₂) batteries, yet their implementation is severely constrained by processing-induced elemental iodine sublimation loss and aggravated polyiodide shuttling during cycling. Herein, unstable active iodine species are decoupled from the conventional cathode and incorporated into a ZnI₂ electrolyte, which is paired with an ultrathick polyethersulfone-polyvinylpyrrolidone@activated carbon (PES-PVP@AC) host electrode to achieve practical high-areal-capacity Zn-I₂ batteries. This scalable phase-inversion electrode-fabrication strategy using a PES-PVP binder blend not only creates highly interconnected electrolyte-infiltration microchannels but also generates an intrinsic PVP-containing hydrogel interphase, thereby simultaneously facilitating rapid ion transport and regulating I₃ ^- generation/dissolution. Mechanistically, the PVP-containing hydrogel interphase coordinates with electrodeposited I₂ to form a stable PVP-I₂ complex, thereby increasing the Gibbs free energy of I₃ ^- formation and rendering the reaction thermodynamically less favorable, while concurrently reducing interfacial H₂O availability to inhibit water-mediated I₃ ^- dissolution/diffusion kinetics. Benefiting from the inherent anti-freezing capability of the ZnI₂-based electrolyte, the Zn-I₂ battery achieves an ultrahigh areal capacity of 7.5 mAh cm^-2 over 3000 cycles at -20°C. Importantly, this strategy enables the direct assembly of Ah-level single-layer pouch cells (∼1.5  Ah) without complex multilayer stacking, offering a practical pathway toward scalable grid energy storage.

PMID:
42742476
Bibliographic data and abstract were imported from PubMed on 15 Sep 2026.

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