Ligand Engineering Toward Robust Sodium Storage in Self‐Supported Metal‐Organic Frameworks

Abstract

Abstract Sodium‐ion batteries capable of charging and discharging rapidly and durably are eagerly demanded to replace current lithium‐ion batteries. However, large Na + ions need more space to accommodate them. Metal‐organic frameworks are promising anode materials, and their structure and performance are governed by organic ligands. Herein, we report a ligand engineering to design metal‐organic frameworks with large conjugated naphthalene‐2,6‐dicarboxylic acid. Self‐supported arrays of metal‐organic frameworks reveal robust sodium storage when used as a binder‐free anode. The uniquely long and conjugated aromatic ligands endow the metal‐organic frameworks with rich sites to accommodate Na + ions, thus enabling a high reversible capacity for sodium storage. As a result, such metal‐organic frameworks exhibit a high capacity of 330 mAh g −1 at 1000 mA g −1 with remarkable rate capability and cycling performance. This work provides an exciting ligand strategy to design high‐capacity metal‐organic framework materials and would find extensive applications in various energy storage systems.