Department of Chemistry, Faculty of Science , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore.
J Am Chem Soc. 2018 Jun 20;140(24):7429-7432. doi: 10.1021/jacs.8b03814. Epub 2018 Jun 6.
Covalent organic frameworks (COFs) with ordered one-dimensional channels could offer a predesigned pathway for ion motion. However, implanting salts into bare channels of COFs gives rise to a limited ion conductivity. Here, we report the first example of polyelectrolyte COFs by integrating flexible oligo(ethylene oxide) chains onto the pore walls. Upon complexation with lithium ions, the oligo(ethylene oxide) chains form a polyelectrolyte interface in the nanochannels and offer a pathway for lithium ion transport. As a result, the ion conductivity was enhanced by more than 3 orders of magnitude compared to that of ions across the bare nanochannels. The polyelectrolyte COFs promoted ion motion via a vehicle mechanism and exhibited enhanced cycle and thermal stabilities. These results suggest that the strategy for engineering a polyelectrolyte interface in the 1D nanochannels of COFs could open a new way to solid-state ion conductors.
共价有机框架（COFs）具有有序的一维通道，可以为离子运动提供预定的途径。然而，将盐植入 COFs 的裸露通道会导致离子电导率有限。在这里，我们通过将柔性聚氧化乙烯（OEO）链整合到孔壁上，报告了首例聚电解质 COFs。在与锂离子络合后，OEO 链在纳米通道中形成聚电解质界面，为锂离子传输提供了途径。结果，与穿过裸露纳米通道的离子相比，离子电导率提高了 3 个数量级以上。聚电解质 COFs 通过载体机制促进离子运动，并表现出增强的循环和热稳定性。这些结果表明，在 COFs 的 1D 纳米通道中构建聚电解质界面的策略可能为固态离子导体开辟一条新途径。
