Monitoring the Solid-State Electrochemistry of Cu(2,7-AQDC) (AQDC = Anthraquinone Dicarboxylate) in a Lithium Battery: Coexistence of Metal and Ligand Redox Activities in a Metal–Organic Framework

By
adopting a facile synthetic strategy, we obtained a microporous
redox-active metal–organic framework (MOF), namely, Cu­(2,7-AQDC)
(2,7-H2AQDC = 2,7-anthraquinonedicarboxylic acid) (1), and utilized it as a cathode active material in lithium
batteries. With a voltage window of 4.0–1.7 V, both metal clusters
and anthraquinone groups in the ligands exhibited reversible redox
activity. The valence change of copper cations was clearly evidenced
by in situ XANES analysis. By controlling the voltage
window of operation, extremely high recyclability of batteries was
achieved, suggesting the framework was robust. This MOF is the first
example of a porous material showing independent redox activity on
both metal cluster nodes and ligand sites.