Quinone-Based Conducting Three-Dimensional Metal-Organic Framework As A Cathode Material For Lithium-Ion Batteries

The low electronic conductivity of organic electrode materials leads to sluggish reaction kinetics and inferior electrochemical performance of lithium-ion batteries. Herein, the conducting three-dimensional metal- organic framework (3D-MOF) (NBu4)(2)Fe-2(DHBQ)(3) was synthesized through a facile aqueous addition reaction. The intramolecular charge delocalization through the robust p-d conjugation between DHBQ ligands and Fe3+ centers is favorable for long-range electron migration, resulting in high electronic conductivity of the 3D hollow (NBu4)(2)Fe-2(DHBQ)(3). When applied as the cathode material, (NBu4)(2)Fe-2(DHBQ)(3) delivers a reversible capacity of 137.2 mA h g(-1) at 10 mA g(-1) and 95.2 mA h g(-1) at 1000 mA g(-1). The capacity retention reached up to 91.4% after 350 cycles at 500 mA g(-1) with about 100% Coulombic efficiency. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy tests reveal that the conjugated carbonyls of DHBQ organic linkers contribute the redox centers and undergo a 5ereaction mechanism during charge and discharge processes. These excellent electrochemical performances could be attributed to the fast electron/ion migration kinetics because of high electronic conductivity and the hollow structure of (NBu4)(2)Fe-2(DHBQ)(3). All the positive results could facilitate the implementation of conductive MOFs for energy conversion and storage acceleration.