中国科学技术大学徐铜文团队报道了三嗪框架膜内的近无摩擦离子传输。相关研究成果发表在2023年4月26日出版的《自然》。

分离工艺和电化学技术的增强，如水电解槽、燃料电池、氧化还原液流电池和离子捕获电渗析，取决于低电阻和高选择性离子传输膜的开发。离子通过这些膜的传输取决于孔结构和孔-分析物相互作用的集体相互作用所施加的整体能垒。然而，设计高效、可扩展和低成本的选择性离子传输膜，为低能垒传输提供离子通道，仍然是一项挑战。

该文中，研究人员开个了一种策略，该策略能够使用具有刚性约束离子通道的共价键合聚合物框架的大面积、独立的合成膜接近离子在水中的扩散极限。近无摩擦离子流通过强大的微孔约束和离子与膜之间的多重相互作用协同实现，例如，Na⁺扩散系数为1.18×10⁹m²s^–1，接近无限稀释纯水中的值，膜的面积比电阻低至0.17Ωcm²。研究人员在快速充电的水性有机氧化还原液流电池中展示了高效膜，该膜在极高的电流密度（高达500mAcm^–2）下具有高能效和高容量利用，并避免了交叉诱导的容量衰减。

这种膜设计概念可以广泛应用于各种电化学装置和精确分子分离的膜。

附：英文原文

Title: Near-frictionless ion transport within triazine framework membranes

Author: Zuo, Peipei, Ye, Chunchun, Jiao, Zhongren, Luo, Jian, Fang, Junkai, Schubert, Ulrich S., McKeown, Neil B., Liu, T. Leo, Yang, Zhengjin, Xu, Tongwen

Issue&Volume: 2023-04-26

Abstract: The enhancement of separation processes and electrochemical technologies such as water electrolysers1,2, fuel cells3,4, redox flow batteries5,6 and ion-capture electrodialysis7 depends on the development of low-resistance and high-selectivity ion-transport membranes. The transport of ions through these membranes depends on the overall energy barriers imposed by the collective interplay of pore architecture and pore–analyte interaction8,9. However, it remains challenging to design efficient, scaleable and low-cost selective ion-transport membranes that provide ion channels for low-energy-barrier transport. Here we pursue a strategy that allows the diffusion limit of ions in water to be approached for large-area, free-standing, synthetic membranes using covalently bonded polymer frameworks with rigidity-confined ion channels. The near-frictionless ion flow is synergistically fulfilled by robust micropore confinement and multi-interaction between ion and membrane, which afford, for instance, a Na+ diffusion coefficient of 1.18×109m2s–1, close to the value in pure water at infinite dilution, and an area-specific membrane resistance as low as 0.17Ωcm2. We demonstrate highly efficient membranes in rapidly charging aqueous organic redox flow batteries that deliver both high energy efficiency and high-capacity utilization at extremely high current densities (up to 500mAcm–2), and also that avoid crossover-induced capacity decay. This membrane design concept may be broadly applicable to membranes for a wide range of electrochemical devices and for precise molecular separation.

DOI: 10.1038/s41586-023-05888-x

Source: https://www.nature.com/articles/s41586-023-05888-x