Developing single crystals of covalent organic polymers (COPs) is highly attractive as they can afford precise structural information for studying internal interactions. Employing dative boron-nitrogen (B-N) bonds to construct single-crystalline COPs is feasible since the dynamic linkages can self-correct errors, thus improving crystallization. In this project, we develop a single-crystal COP with a nanobelt structure, namely CityU-26, via B-N-driven-assembly between 4,4',5,5'-tetrakis(4-(pyridin-4-yl)phenyl)-2,2'-bi(1,3-dithiolylidene) and 1,4-bis(benzodioxaborole) benzene. The B-N coordination between these units gives rise to one-dimensional (1D) nanobelts, and hydrogen bonding interactions between the nanobelts lead to the formation of a three-dimensional (3D) supramolecular structure. CityU-26 demonstrates an impressive sodium storage capability of 365 mA h g-1 with a current density of 150 mA g-1, and the capability could reach 315 mA h g-1 at 750 mA g-1. The outstanding sodium storage behaviors of CityU-26 underscore the functionalization of B-N polymers, providing a promising platform for the development of efficient energy materials.
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