Haloaromatic Reduction-Induced Formation of a High Surface Work Function Protective Layer on a Lithium Electrode for Stable Lithium Metal Batteries

A liquid-phase strategy for stabilizing lithium metal electrodes in lithium metal batteries using halogen-substituted benzophenone compounds (4-X-BzPh, X = F, Cl, and Br) is performed. These compounds undergo spontaneous haloaromatic reduction upon contact with lithium, forming thin and uniform protective layers of lithium halides (LiX, where X = F, Cl, and Br). This process enables homogeneous passivation without the need for complex fabrication techniques. Among the LiX species, LiF exhibits the highest surface work function and the strongest electron-blocking properties, effectively suppressing dendrite formation and electrolytic decomposition. Moreover, the proposed approach is successfully scaled to pouch cell configurations, demonstrating compatibility with practical battery systems. This haloaromatic compound-based liquid modification strategy enhances the reversibility and stability of lithium metal electrodes through the spontaneous formation of functional LiX interphases and leveraging the protective characteristics of LiX layers.