Quantitative Skeletal-Charge Engineering of Anion-Selective COF Membrane for Ultrahigh Osmotic Power Output

作者：Shuang Zheng, Xing Liu, Chunlei Wang, Zhaofeng Ouyang, Xiaohu Zhang, Shuai Bi, Guosheng Shi, Qing Xu, Joseph S. Francisco, Gaofeng Zeng · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.5c03492 · 被引用次数：48 · 研究领域：Membrane-based Ion Separation Techniques、Fuel Cells and Related Materials、Membrane Separation Technologies

Osmotic energy contained in water bodies can generate abundant renewable electricity through reverse electrodialysis (RED) that relies on ion permselective membranes. Anion-permselective membrane RED offers a stable and sustainable energy output potential by maintaining a consistent driving force across the membrane, providing advantages in sustainability and versatility over cation-selective membranes. But significant challenges persist in developing anion-selective membranes that feature high selectivity and low impedance. Herein, this study presents the development of an anion-permselective osmotic power generation system using a free-standing chloride-selective covalent organic framework (COF) membrane. Inspired by biological chloride channels, the membrane is engineered with smooth, straight, and highly charged nanochannels for rapid chloride-anion transport. Its inner structure is stoichiometrically controlled to atomically distribute positive charges on the COF intraplane rings without introducing heterometal atoms or branch groups, enabling selective and efficient single-directional movement of anions. The RED device with this ionic-COF membrane achieves a remarkable output power density of 239.6 W m –2, outperforming commercial benchmarks by 2 orders of magnitude, with low intermediate resistance under demanding gradients. Theoretical simulations corroborate that anion transport within ionic-COF membranes is governed by electrostatic interactions with the charged ske...