Exploration of a one-dimensional iron-based coordination polymer for enhanced lithium storage capabilities†

Abstract

Taking advantage of the high redox activity and excellent structural stability properties of coordination polymers (CPs), we have successfully prepared a one-dimensional CP, {[Fe(pyzdc)]·2H₂O}_n (Fe-1D), by a hydrothermal method with pyrazine-2,3-dicarboxylic acid (H₂pyzdc) as the ligand and iron as the metal center to improve the deficiencies of organic electrode materials in terms of specific capacity and cycling stability in lithium-ion batteries (LIBs). The one-dimensional chains are connected to each other by hydrogen bonds, and a three-dimensional supramolecular network is constructed, which not only enhances the stability of the material during the charge–discharge cycle, but also promotes the rapid transport of ions by virtue of its porous structure and ordered ion channels. Consequently, Fe-1D demonstrates outstanding cycling stability, achieving a remarkable reversible capacity of 833 mAh g⁻¹ after 300 cycles at 200 mA g⁻¹. Theoretical calculations further illustrate that after introducing the metal center into the ligand, Fe-1D can store 12 lithium ions, while significantly narrowing the energy gap, suggesting that Fe-1D has abundant lithium storage sites and good electrochemical activity. Both experimental and theoretical analyses underscored the pivotal role of redox-active metal–organic materials in designing high-performance anodes for rechargeable batteries.