Coordination Structures Integrating Multiple Redox-Active Centers for Enhanced Zinc-Ion Storage

Aqueous zinc-ion batteries (AZIBs) are considered promising alternatives to lithium-ion batteries (LIBs) owing to their cost efficiency and eco-friendliness. However, the instability of the electrode materials poses a significant obstacle to broader applications. Herein, the synthesis, characterization, and zinc-ion storage properties of a vanadium coordination structure (V-INA) that uses VO2+ as the coordination center and isonicotinic acid (INA) as the organic ligand have been reported. Characterization techniques confirmed that the spacious lattice spacing and larger pore structure of V-INA create an efficient and stable pathway for zinc-ion migration. Note that within the V-INA structure, both the −COO– and C═N groups act in tandem as redox-active centers as well as zinc-ion hosts, and the valence change of vanadium (V4+/V5+) in VO2+ boosts the capacity of the battery. Benefiting from unique advantages of materials, V-INA achieves an unprecedented stability with a capacity retention of 97.25% after 1500 cycles at 5 A g–1 as well as still delivers 123 mAh g–1 reversible capacity after 2000 cycles at 10 A g–1 with a Coulombic efficiency of ∼100%. This work can inspire the design of coordination structures containing multiple redox-active centers as cathode materials for high-performance rechargeable AZIBs.