An Adaptive Ionic Sieve: Flexible Hydrogen‐Bonded Organic Frameworks Decouple the Trade‐Off Between Zn Ions Desolvation and Mass Transfer

ABSTRACT

Efficient ion desolvation and rapid mass transport are crucial yet often competing requirements for stabilizing Zn anodes in aqueous Zn‐ion batteries. This dilemma arises because ion desolvation introduces additional energy barriers that increase ion diffusion resistance. To reconcile this inherent trade‐off, a hydrogen‐bonded organic framework (HOF) based on C ₃ ‑symmetric trigonal carboxyl ligands is engineered as an ion‐sieving interface. This design integrates precise pore size control with tailored chemical environment to regulate Zn ²⁺ desolvation behavior. As expected, the flexible HOF incorporating an electron‐deficient triazine core (HOF‐TAT) dynamically strips solvated water molecules while maintaining continuous ion flux. This process fosters a gradient solid electrolyte interphase that synergizes with the self‐adaptive porous framework to guide dense (101)‐oriented Zn deposition. The HOF‐TAT@Zn symmetric cells stably cycle exceeding 3400 h at 5 mA cm ⁻² . Furthermore, the iodophilic porous framework immobilizes shuttling polyiodides through strong physicochemical interactions. When integrated with an ultrathin Zn anode (10 µm), the Zn‐iodine batteries deliver a high‐rate capacity (142.2 mAh g ⁻¹ at 5 A g ⁻¹ ) and long‐term lifetime (50 000 cycles). This work offers an intelligent strategy to concurrently overcome the high energy barriers of ion desolvation and the kinetic limitations of ion transport for building advanced electrochemical devices.