Bidirectional Interfacial Chemical Regulation Enables Durable Aqueous Zn‐I 2 Batteries

Aqueous Zn‐I 2 batteries hold great promise for large‐scale energy storage, yet their practical deployment is hindered by coupled interfacial instabilities at both electrodes, where Zn‐anode parasitic reactions and cathodic polyiodide shuttle mutually aggravate each other. Herein, we propose a bidirectional interfacial‐regulation strategy integrating hydrogen‐bond‐confined polyiodide chemistry with chelation‐mediated anode interfacial reconstruction. Using N‐acetyl‐L‐glutamic acid (NAG) as a molecular regulator, the acetamide group interacts with polyiodides through N‐H···I hydrogen bonding, thereby facilitating polyiodide conversion while suppressing shuttle. Meanwhile, the carboxyl groups enable preferential adsorption of NAG on the Zn surface via bidentate chelation, which reconstructs the interfacial molecular environment, suppresses parasitic reactions, and regulates Zn deposition toward enhanced reversibility and preferential Zn(002) growth. As a result, the Zn||Zn symmetric cell achieves stable cycling for up to 3000 h at 2 mA cm −2 and 2 mAh cm −2 , and still maintains stable Zn plating/stripping for over 200 h even at 10 mA cm −2 and 10 mAh cm −2 . Moreover, the Zn‐I 2 full cell delivers 97.5% capacity retention after 3700 cycles at 1 A g −1 and exhibits stable long‐term cycling over 32000 cycles at 10 A g −1 . These findings highlight bidirectional molecular interfacial regulation as an effective route to high‐durability aqueous Zn‐I 2 batteries.