Anthraquinone Substituents Regulate the Ion-Transport Sites in iHOFs for Efficient Transport of Alkali-Metal Ions

The designability of crystalline framework materials holds promise for the development of stable solid-state electrolytes with high ionic conductivity. In this study, we present three anthraquinone-based ionic hydrogen-bonded organic frameworks ( iHOF-21–23 ), which possess 2D sandwich-shaped hydrogen-bonding networks. By modulating the anthraquinone substituents, the three iHOFs exhibit distinct ion-transport sites. Specifically, both carbonyls in the structure of iHOF-22 are ion-transport sites, whereas only one carbonyl in each of iHOF-21 and iHOF-23 is, and thus iHOF-22 exhibits higher ionic conductivities. The ionic conductivities of Li +, Na +, and K + of iHOF-22 at 30 °C are 1.37 × 10 –4, 1.14 × 10 –4, and 9.76 × 10 –5 S cm –1, respectively, which are 16–47% higher than those of iHOF-21 and iHOF-23 . The design of the iHOFs for multidimensional ion transport provides valuable insights for the development of solid-state electrolytes for various ion batteries.