Redox‐Catalytic p‐Toluquinone With Dynamic Proton‐Iodine Modulation for High‐Capacity and Durable Zn–I 2 Battery

Aqueous Zn─I 2 batteries offer an attractive route toward risk‐free, cost‐efficient, and sustainable energy storage. However, their practical implementation is hindered by the challenges of sluggish iodine conversion kinetics and severe polyiodide shuttling. Herein, we reported a bio‐derived p‐toluquinone (TQ) confined onto porous activated carbon (denoted as TQ@AC) as redox‐catalytic cathode that leverages its quinoid backbone and carbonyl redox centers to simultaneously stabilize TQ redox cycling and boost iodine conversion efficiency. According to a combination of in/ex situ analyses and theoretical calculations, carbonyl groups within TQ serve as proton storage sites, and undergo reversible proton‐coupled electron transfer (PCET) process during battery working. Moreover, protonated carbonyl sites effectively confine iodine species via proton‐driven C═O/C─OH reaction and catalyze highly‐reversible iodine conversion, achieving a four‐electron proton‐iodine dual‐redox mechanism. Therefore, electrolytic Zn─I 2 battery based on TQ@AC cathode delivers an impressive capacity of 410 mAh g −1 , superior rate capability and achieves 85% capacity retention over 63 000 cycles. Additionally, the outstanding working stability and excellent temperature tolerance of the pouch cell within −15°C–45°C underscore its practical applicability, highlighting the effectiveness of synergistic organic‐iodine modulation for advanced Zn‐halogen batteries.