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

Abstract

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 2 cathode wrapped in situ by a conjugated poly(phenylenediamine) (pPDA) layer, denoted VO 2– pPDA, which enables highly reversible and efficient V 5+ /V 4+ /V 3+ and I − /I 0 redox reactions in ZnI 2 ‐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 2 and interfacial iodine anchoring. Meanwhile, the π‐conjugated framework of poly(PDA) collaborated with VO 2 to catalyze the high‐efficiency iodine conversion. Due to V‐I co‐regulation, Zn//VO 2 ‐pPDA battery exhibited a high working voltage of 1.09 V, ultrahigh capacity of 610 mAh g −1 , 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.