One-Dimensional Croconate-Based Fe-CP as a High-Performance Anode Material for Lithium-Ion Batteries

Coordination polymers (CPs) have attracted greater scientific attention as promising electrode materials for lithium-ion batteries (LIBs) due to their diverse and versatile structural chemistry. This study introduces a croconate-based one-dimensional CP, namely [Fe(C₅O₅)(H₂O)₃]_n) (referred to as Fe-CP), as an efficient anode material with high-performance characteristics for rechargeable LIBs. The ligand with abundant redox sites coordinating to the transition metal ion endowed the anode material with a remarkable stability in the electrolyte, in addition to high capacity, high-rate capability, and high cycling performance during charging/discharging process. The Fe-CP has a unique chain-based supramolecular structure, setting it apart from other porous three-dimensional molecular materials. The presence of unrestricted channels between the chains facilitates the diffusion of lithium ions in this unique structure. When tested at 100 mA g^-1 over a range of voltages between 0.01 and 2.4 V, the Fe-CP anode demonstrated a noteworthy specific capacity of 521 mA h g^-1 over 140 cycles. Moreover, the Fe-CP anode material exhibited excellent rate performance and demonstrated favorable cyclability. Following exposure to high charging and discharging rates of 2 A g^-1, the anode ultimately regained its initial capability when the current rate was back at 100 mA g^-1.