Unraveling the Fluoride-Induced\nInterface Reconstruction\nAcross Lead-Based Hierarchical MnO<sub>2</sub> Anode in Zinc Electrowinning

Although the hierarchical manganese dioxide film electrode\nshows\npromise as a durable and catalytically active anode for zinc electrowinning,\nit often fails and deactivates when it is exposed to fluoride-rich\nenvironments. The lack of understanding regarding the mechanism behind\nfluoride-induced irreversible interface reconstruction hinders their\npractical application in large-scale energy-saving and pollution-reduction\nefforts. Here, we conducted multidimensional operando investigations\nto gain insights into the dynamic evolution across the film electrode\ninterface with temporal and spatial resolution. Our findings reveal\nthat electroosmosis of F<sup>–</sup> initially triggers structural\ncollapse and subsequent reconstruction of [MnO<sub>6</sub>] units,\nfollowed by interaction with the spontaneous oxide film at the surface\nof lead substrate. Experimental studies and theoretical calculations\nindicate that F<sup>–</sup> facilitates the irreversible transformation\nof γ-MnO<sub>2</sub> into more stable yet protective catalytic\ndual-defective α-MnO<sub>2</sub>. Additionally, lower levels\nof F<sup>–</sup> at the interface promote a change in microenvironmental\npH within porous PbSO<sub>4</sub>, triggering the development of microporous\ncorrosion-resistant β-PbO<sub>2</sub> as the dominant phase.\nThe combined effects of MnO<sub>2</sub> and interphase evolution effectively\nexplain the abnormally elevated oxygen evolution overpotential. Then,\nthe proposed appropriate application scenarios based on the corrosion\nbehavior will serve as a practical guide for the implementation of\nthe hierarchical manganese dioxide film electrode.