Fast\nIon Transport Pathway Provided by Polyethylene\nGlycol Confined in Covalent Organic Frameworks

Covalent organic\nframeworks (COFs) with well-tailored channels\nare able to accommodate ions and offer their conduction pathway. However,\ndue to strong Coulombic interaction and the lack of transport medium,\ndirectly including lithium salts into the channels of COFs results\nin limited ion transport capability. Herein, we propose a strategy\nof incorporating low-molecular-weight polyethylene glycol (PEG) into\nCOFs with anionic, neutral, or cationic skeletons to accelerate Li<sup>+</sup> conduction. The PEG confined in the well-aligned channels\nretains high flexibility and Li<sup>+</sup> solvating ability. The\nion conductivity of PEG included in a cationic COF can reach 1.78\n× 10<sup>–3</sup> S cm<sup>–1</sup> at 120 °C.\nThe simplicity of this strategy as well as the diversity of crystalline\nporous materials holds great promise to design high-performance all-solid-state\nion conductors.