A Redox‐Active 2D Metal–Organic Framework for Efficient Lithium Storage with Extraordinary High Capacity

Abstract

Metal–organic framework cathodes usually exhibit low capacity and poor electrochemical performance for Li‐ion storage owing to intrinsic low conductivity and inferior redox activity. Now a redox‐active 2D copper–benzoquinoid (Cu‐THQ) MOF has been synthesized by a simple solvothermal method. The abundant porosity and intrinsic redox character endow the 2D Cu‐THQ MOF with promising electrochemical activity. Superior performance is achieved as a Li‐ion battery cathode with a high reversible capacity (387 mA h g−1), large specific energy density (775 Wh kg−1), and good cycling stability. The reaction mechanism is unveiled by comprehensive spectroscopic techniques: a three‐electron redox reaction per coordination unit and one‐electron redox reaction per copper ion mechanism is demonstrated. This elucidatory understanding sheds new light on future rational design of high‐performance MOF‐based cathode materials for efficient energy storage and conversion.

Recent advances in process engineering and upcoming applications of metal–organic frameworks

“…(b) The evolution of electronic states of the repeating coordination unit of 2D Cu-THQ MOF during the charge/discharge process. Reproduced with permission from [372] . Copyright 2020 John Wiley and Sons.…”

“…A novel two-dimensional (2D) copper–benzoquinoid MOF (Cu-THQ) was also prepared for the cathode material of LIBs, which showed excellent electrochemical performance [372] . Electrochemical studies revealed that Cu-THQ had a high reversible specific capacity of 387 mAh g −1 at a current density of 0.05 A g −1 , a high power density of 775 Wh kg −1 , and efficient cycling stability, with 85% retained capacity (340 mAh g −1 ) after 100 cycles.…”

Successive Storage of Cations and Anions by Ligands of π–d‐Conjugated Coordination Polymers Enabling Robust Sodium‐Ion Batteries

“…[1,6,[10][11][12][13][14][15][16][17] Thea bundant unsaturated bonds and functional groups in the p-conjugated ligands and the multi-valences of the metal ions make it also possible to accept or lose electrons and thereby batteries with high capacity could be expected. [10,[18][19][20][21][22][23][24][25][26][27] However,s uch multielectron redox reactions also result in the uncontrollable synthesis,avariety of by-products and the difficulty in identification of the products. [19] Fortunately,t he structural and valent variation after acceptance/loss of electrons during the battery cycling provides ag ood platform for deep understanding the obtained p-d conjugated coordination polymers.…”

A Two‐Dimensional Metal–Organic Polymer Enabled by Robust Nickel–Nitrogen and Hydrogen Bonds for Exceptional Sodium‐Ion Storage

“…Metal-organic frameworks (MOFs) with Zn 2+ and Fe 3+ as the metal nodes and organic carboxylates as the ligands were attempted for lithium-ion batteries (LIBs) and SIBs,b ut the metal-organic ligand bonds were not strong enough to ensure redox reactions,a nd instead they broke to work via typical conversion reactions. [15][16][17] Recently,B aosg roup reported two-dimensional (2D) metal-hexaaminobenzenef rameworks,w hich presented high pseudocapacitance based on the redox of the benzoid amine species. [18,19] Romansa nd Wangsg roups synthesized one-dimensional metal-organic polymers (MOPs) with 1,2,4,5-benzenetetramine as the organic ligand for LIBs and SIBs,respectively.…”