Commencing mild Ag–Zn batteries with long-term stability and ultra-flat voltage platform

Alkaline Silver (Ag)-Znic (Zn) batteries have been suffering from poor cyclic stability for over one century but the comprehensively improving protocol is still in vacancy with big challenge. Here, we commence a mild Ag–Zn battery to simultaneously solve the cathode dissolving issue and anode dendrite issue. The battery proceeds through anionic halides as charging carriers for cathode reactions, endowing two phase transition process with ultra-flat discharging voltage plateau. The battery delivered unprecedently elongated cyclic lifetime to 1300 cycles in contrast to conventional alkaline Ag–Zn battery (<100 cycles). This work not only solved the long-term cyclic issue of Ag–Zn battery but also would act as a model system to introduce mild electrolyte and anionic charging carriers into other aqueous battery systems for performance improvement.