Vanadium-Iodine Co-Regulation Enabled by Trifunctional Conjugated Organic Interface for High-Energy and Robust Zn Batteries.

Wang, Yueyang; Wang, Runze; Yu, Linfeng; Wei, Shiqiang; Shifa, Tofik Ahmed; Lv, Yanan; Zhang, Xiaoru; Li, Qi et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

Aqueous Zn batteries (AZBs) utilizing vanadium-iodine dual energy storage mechanisms hold great promise for large-scale energy storage applications. Yet, the development of such AZBs is plagued by severe vanadium dissolution and uncontrolled polyiodide shuttling during the multi-step electron transfer process. Herein, we reported a core-shell VO<sub>2</sub> cathode wrapped in situ by a conjugated poly(phenylenediamine) (pPDA) layer, denoted VO<sub>2-</sub>pPDA, which enables highly reversible and efficient V<sup>5+</sup>/V<sup>4+</sup>/V<sup>3+</sup> and I<sup>-</sup>/I<sup>0</sup> redox reactions in ZnI<sub>2</sub>-containing electrolytes. According to in/ex situ characterizations and theoretical calculation results, abundant ─C═N─ moieties in poly(PDA) enabled a synergistic optimization for the stabilization of VO<sub>2</sub> and interfacial iodine anchoring. Meanwhile, the π-conjugated framework of poly(PDA) collaborated with VO<sub>2</sub> to catalyze the high-efficiency iodine conversion. Due to V-I co-regulation, Zn//VO<sub>2</sub>-pPDA battery exhibited a high working voltage of 1.09 V, ultrahigh capacity of 610 mAh g<sup>-1</sup>, and outstanding lifespan over 40 000 cycles. Moreover, a practical 1.0 Ah pouch cell further demonstrated the strong application potential of this system, highlighting the effectiveness of multifunctional interfacial organic engineering for high-performance Zn batteries.