1D Anionic Covalent Organic Frameworks With Directed Migration of Alkali Metal Ions for High Ionic Conductivity

Abstract Rational construction of high‐performance ionic conductors is a critical challenge in the field of energy storage. In this study, a series of 1D anionic titanium‐based covalent organic frameworks (COFs) containing abundant alkali metal ion migration sites, namely, COF‐ M ‐ R ( M = Li, Na, K; R = H, Me, Et), is constructed. The integration of negative TiO 6 2− sites on 1D anionic COFs allows alkali metal cations to migrate directly through the channels. Meanwhile, the π–π stacking of 1D chain‐to‐chain allows the distribution of ion‐migration sites in 2D planes. In view of this, multidimensional ionic transport in COFs is realized to achieve high ionic conductivity. COF‐ M ‐ R s exhibit an increased ionic conductivity as the counterions change from Li + to Na + to K + . Notably, COF‐Na‐Et has an impressive ionic conductivity as high as 0.81 × 10 −3 S cm −1 . The different decorated groups (H, Me, and Et) on the skeleton influence the dissociation of the cation from the polyanion. This study offers deep insights into the design of COF‐based solid‐state electrolytes to achieve high ionic conductivity by increasing the ionic transport dimensions.