Axial Coordination Induced Electron Delocalization and p-p Orbital Hybridization in Single-Atom Catalysts Boosts Zn²⁺...

Aqueous zinc-ion batteries have emerged as promising candidates for next-generation energy storage due to their superior safety and lower cost. However, the sluggish desolvation kinetics of hydrated zinc ions at anode causes critical issues, including dendritic growth, hydrogen evolution reaction (HER), and anode corrosion. Herein, taking Sb single-atoms (SAs) as a proof-of-concept, a F-axial coordination engineering strategy is proposed to accelerate the desolvation kinetics and thus ensure robust cycling stability of Zn anode. Theoretical calculations reveal that the electron delocalization triggered by F-axial coordination and p-p orbital hybridization between Sb and F atoms strengthens the affinity for Zn. Electrochemical analysis and in situ/ex situ spectroscopy characterizations demonstrate that the introduction of F-axial coordination can effectively reduce the energy barrier for the desolvation process of hydrated zinc ions, inhibit HER, uniform Zn²⁺ diffusion, and enable lateral Zn deposition. Consequently, the symmetric zinc battery based on F-axial coordinated Sb SAs (F-Sb SAs)-modified Zn anode features unprecedented stability up to 6000 and 1200 h at 5 and 20 mA cm^-2, respectively. Furthermore, the fabricated F-Sb SAs@Zn||I₂ battery exhibits remarkably long durability at a high current density of 10 A g^-1, maintaining 94.3% of capacity even after 100 000 cycles.