Large-Pore Mesoporous Covalent Organic Frameworks Fast Ion Sieves by Kinetics-Mediated Micelle Assembly for Aqueous Batteries

Abstract

Developing ion-selective interphases with functional groups that promote uniform Zn2+ deposition and repel polyiodides is promising for stable Zn–I2 batteries. Covalent organic frameworks (COFs) are compelling for such design owing to their programmable skeletons and tunable functional moieties, but their predominant microporosity locks active sites, impeding application. Herein, we establish a kinetics-mediated micelle assembly strategy for the controllable synthesis of MesoCOF nanospheres and construct the first MesoCOFs library with diverse components (5 types), mesophases (spherical, dendritic, walnut-like), pore sizes (15.8–21.6 nm), and particle diameters (60–390 nm). This approach adjusts reaction kinetics into the non-classical growth regime, suppressing self-growth of COF precursors and enabling cooperative assembly with micelles, as confirmed by kinetics analysis. This versatile synthesis enables an ethylene-linked MesoCOF-based fast ion-sieve. In-situ analyses and theoretical calculations reveal that the large mesopores unlock triazine sites, accelerating Zn2+ desolvation, homogenizing ionic flux, and blocking polyiodide shuttling. Consequently, the MesoCOF-coated Zn anode enables stable Zn plating/stripping for over 2700 h at 5 mA cm‒2, and Zn–I2 full cells deliver outstanding cycling stability with 95% capacity retention over 550 cycles at 0.1 A g‒1. This work heralds a new paradigm for MesoCOF design, unlocking their potential for dendrite- and shuttle-free energy storage.