3D covalent organic framework membrane with fast and selective ion transport
Tianhao Zhu, Yan Kong, Bohui Lyu, Li Cao, Benbing Shi, Xiaoyao Wang, Xiao Pang, Chunyang Fan, Chao Yang, Hong Wu, Zhongyi Jiang
Abstract
Abstract 3D ionic covalent organic framework (COF) membranes, which are envisioned to be able to break the trade-off between ion conductivity and ion selectivity, are waiting for exploitation. Herein, we report the fabrication of a 3D sulfonic acid-functionalized COF membrane (3D SCOF) for efficient and selective ion transport, using dual acid-mediated interfacial polymerization strategy. The 3D SCOF membranes possess highly interconnected ion transport channels, ultramicroporous pore sizes (0.97 nm), and abundant sulfonate groups (with a high ion exchange capacity of 4.1 mmol g −1 ), leading to high proton conductivity of 843 mS cm −1 at 90 °C. When utilized in osmotic energy conversion, a high power density of 21.2 W m −2 , and a remarkable selectivity of 0.976 and thus an exceptional energy conversion efficiency of 45.3% are simultaneously achieved. This work provides an alternative approach to 3D ionic COF membranes and promotes the applications of 3D COFs in ion transport and separation.