An Iron-Coordinated Metal-Covalent Organic Framework as High-Capacity Anode Material with Ultralong Life for Lithium-Ion Batteries

Metal-covalent organic frameworks (MCOFs), a novel class of organic electrode materials that integrate the electrical conductivity of metal–organic frameworks (MOFs) with the structural stability of covalent organic frameworks (COFs), demonstrate remarkable potential for lithium-ion battery (LIBs) applications. In this study, a novel iron-coordinated MCOF of DHBD-TFP-Fe-COF was synthesized via a one-step coordination strategy using 3,3′-dihydroxybenzidine (DHBD) and 2,4,6-triformylphloroglucinol (TFP) as precursors in the presence of FeCl3·6H2O, which exists in an enol-imine form due to the coordination of iron ions. Compared with the counterpart of DHBD-TFP-COF without Fe3+-coordination, DHBD-TFP-Fe-COF exhibits superior electrochemical performance as an anode material for LIBs, retaining the specific capacities of 400 mAh g–1 after 3000 cycles at 1 A g–1 and 200 mAh g–1 after 12,000 cycles at 5 A g–1. The Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) characterizations indicate the involvement of Fe3+ in charge storage, contributing to improved electrochemical performance.