Enhancing Ion Dynamics and Ion-Enrichment Through Electronegative Azolate Framework for Zinc Anode Stabilization

Abstract

Zinc anodes are prone to surface corrosion and dendrite formation due to the complex interactions between cations and water molecules. The high surface charge density of cationic groups, coordinated by six water molecules, leads to the reduction of bound H₂O, promoting OH⁻ ion formation and accelerating zinc corrosion. This process generates by-products such as Zn₄SO₄(OH)₆·xH₂O, while the tip effect further exacerbates the non-uniform deposition of zinc ions, fostering dendrite growth. Additionally, interfacial concentration polarization impedes ion migration, hindering the overall ion kinetics of the system. To mitigate these issues, we introduce an electronegative three-dimensional m-PO₃ ([N(CH3)4]+1/3·[Zn2(mPO3)2/3(5-mtz)3]) as an artificial interface layers (AILs) on the zinc anode. This AIL serves dual purposes: preventing direct water contact with the zinc surface, thus inhibiting hydrogen evolution and corrosion, and enhancing ion enrichment at the interface. Impedance measurements at various temperatures reveal that the activation energy (Eₐ) of the m-PO₃@Zn interface (18.29 kJ mol-1) is lower than that of the pure zinc anode, indicating a significant improvement in ion migration dynamics. As a result, the m-PO₃@Zn anode demonstrates exceptional cycling stability, with a Coulombic efficiency of 95.6%, highlighting its potential for long-term, high-performance zinc-based batteries.

Keywords: electronegative MOF, ion dynamics, activation energy, ion enrichment, Dendrite suppression