Spontaneous Interface Layer Engineering of Ag2Mn8O16 Cathode via Anodic Oxidation Strategy toward High-Performance Aqueous Zinc-Ion Batteries

The disproportionation reaction of Mn3+ ions induced by the Jahn–Teller effect hinders the practical application of Mn-based oxides in aqueous zinc-ion batteries (AZIBs). Herein, Ag2Mn8O16 is reported as a promising cathode for AZIBs, and its performance improvement mechanism in a chlorine-containing electrolyte is comprehensively investigated. As demonstrated, the partial deintercalation of silver ions promotes the valence state and reactivity of the Mn element in Ag2–x Mn8O16 and favors the formation of the AgCl layer. As an electronic insulator and ionic conductor, the AgCl layer can effectively inhibit the manganese dissolution, reduce the activation energy barrier, and facilitate the zinc diffusion kinetics in Ag2Mn8O16. As expected, the Ag2Mn8O16 cathode exhibits high capacity of 369.2 mAh g–1 at 0.1 A g–1 and 269.6 mAh g–1 after 200 cycles at 0.5 A g–1 in the optimized chlorine-containing electrolyte, implying the in situ interface engineering can eliminate the dilemma of dissolution and inactivation of Mn-based oxides in aqueous batteries.