Nucleophilic Substitution Enables Robust Fluorinated Interphase for Low <i>N</i> / <i>P</i> Ratio Zinc Battery

Abstract

Abstract Aqueous zinc (Zn) batteries have garnered considerable interest as a promising, safe, and sustainable energy storage technology. Nevertheless, their widespread commercialization is hindered by critical challenges, particularly the limited Zn reversibility caused by persistent electrolyte decomposition and uncontrolled dendritic growth. In this study, we propose a chemical strategy involving nucleophilic ethoxide ions, generated via ethanol deprotonation, to induce defluorination of the trifluoromethanesulfonate anion. This approach facilitates the in situ formation of a fluorinated protective interphase on the Zn anode surface. The engineered interphase exhibits remarkable mechanical robustness, as demonstrated by substantially improved Zn Coulombic efficiency at both high and low current densities as well as high Zn utilization rates. Furthermore, this surface modification strategy enables the Zn 0.25 V 2 O 5 /Zn powder batteries to achieve unprecedented cycling stability, including prolonged operation under demanding low N/P ratio conditions (&lt;2:1) and high areal capacity (&gt;2 mAh cm −2 ).