An adsorptive additive enhancing reversibility of zinc metal electrodes

Aqueous zinc ion batteries (AZIBs) are considered promising candidates for next-generation energy storage systems due to their high safety and low cost. However, their practical development is hindered by uncontrolled dendrite growth and side parasitic reactions at the Zinc (Zn) anodes. In this study, we introduce the adsorptive additive ammonium perfluoro (2-methyl-3-oxahexanoate) (APFA) to regulate Zn deposition behavior. The electrostatic repulsion between PFA − anions and the high-charge-density Zn protrusions during the cathodic process promotes preferential adsorption of PFA − anions on relatively flat Zn surfaces. This selective adsorption accelerates local reaction kinetics via electric double layer (EDL) modulation, leading to a levelled Zn surface. Furthermore, the surface activity of PFA − repels free H 2 O molecules from the Zn surface, thereby suppressing water-induced side reactions. With only a trace amount of APFA (1 mM) added to the electrolyte, Zn Zn symmetric cells exhibit stable cycling for over 1600 h at a current density of 1 mA cm −2 and 1 mAh cm −2 . This study presents a facile and effective strategy for stabilizing Zn anodes in AZIBs.