Yin Shijie, Li Jianguo, Lai Zhuozhi, Meng Qing-Wei, Xian Weipeng, Dai Zhifeng, Wang Sai, Zhang Li, Xiong Yubing, Ma Shengqian, Sun Qi
Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
Nat Commun. 2024 Sep 17;15(1):8137. doi: 10.1038/s41467-024-52487-z.
Efficient energy conversion using ions as carriers necessitates membranes that sustain high permselectivity in high salinity conditions, which presents a significant challenge. This study addresses the issue by manipulating the linkages in covalent-organic-framework membranes, altering the distribution of electrostatic potentials and thereby influencing the short-range interactions between ions and membranes. We show that a charge-neutral covalent-organic-framework membrane with β-ketoenamine linkages achieves record permselectivity in high salinity environments. Additionally, the membrane retains its permselectivity under temperature gradients, providing a method for converting low-grade waste heat into electrical energy. Experiments reveal that with a 3 M KCl solution and a 50 K temperature difference, the membrane generates an output power density of 5.70 W m. Furthermore, guided by a short-range ionic screening mechanism, the membrane exhibits adaptable permselectivity, allowing reversible and controllable operations by finely adjusting charge polarity and magnitude on the membrane's channel surfaces via ion adsorption. Notably, treatment with KPO solutions significantly enhances permselectivity, resulting in a giant output power density of 20.22 W m, a 3.6-fold increase over the untreated membrane, setting a benchmark for converting low-grade heat into electrical energy.
使用离子作为载体进行高效能量转换需要在高盐度条件下保持高选择性透过的膜，这是一项重大挑战。本研究通过操纵共价有机框架膜中的连接键来解决这一问题，改变静电势分布，从而影响离子与膜之间的短程相互作用。我们表明，具有β-酮烯胺连接键的电荷中性共价有机框架膜在高盐度环境中实现了创纪录的选择性透过。此外，该膜在温度梯度下保持其选择性透过性，提供了一种将低品位废热转化为电能的方法。实验表明，在3M KCl溶液和50K温差下，该膜产生的输出功率密度为5.70W/m。此外，在短程离子筛选机制的指导下，该膜表现出适应性选择性透过性，通过离子吸附在膜通道表面精细调节电荷极性和大小，实现可逆和可控操作。值得注意的是，用KPO溶液处理显著提高了选择性透过性，产生了20.22W/m的巨大输出功率密度，比未处理的膜增加了3.6倍，为将低品位热转化为电能树立了标杆。
