Antioxidant Interfaces Enabled by Self-Deoxidizing and Self-Dehydrogenating Redox Couple for Reversible Zinc Metal Batteries

Parasitic electrolyte reactions and dendrite growth make Zn metal anodes with high Zn utilization rates (ZURs) more inaccessible, holding back the advance of aqueous zinc metal batteries (AZMBs). Here, sodium isoascorbate (SIA) is introduced to aqueous electrolytes as a self-deoxidizing and self-dehydrogenating additive. Coexisting C6H7O6-/C6H5O6- couple spontaneously captures dissolved oxygen and eliminates generated hydrogen by acting as a redox buffer, which leads to the creation of antioxidant Interfaces due to an in situ formed ZnCO3-dominated solid electrolyte interphase (SEI). This SEI enables the (100) faceted electrode with dendrite-free and non-corrosive Zn plating/stripping, thus yielding a Coulombic efficiency of 99.7% up to 1100 h at 5 mAh cm-2, as well as a stable cycle sustaining for over 335 h under a high ZUR of 85.5%. Full-cell properties are demonstrated by matching a poly(3,4-ethylenedioxythiophene) intercalated vanadium oxide (PEDOT-V2O5) cathode, which harvests a high capacity of 302 mAh g-1 (at 0.01 A g-1) and holds 94.2% capacity retention over 600 cycles (at 1 A g-1) under practical conditions (N/P = 4.2 and E/C = 7.6 mu L mg-1). These findings provide a new solution for electrolyte design for industrializing AZMBs. Coexisting C6H7O6-/C6H5O6- redox couple in aqueous electrolyte with sodium isoascorbate as a self-deoxidizing and self-dehydrogenating additive spontaneously captures dissolved oxygen and eliminates generated hydrogen. Antioxidant Interfaces are created on the Zn anode due to the formation of a ZnCO3-dominated solid electrolyte interphase, which enables the (100) faceted electrode with dendrite-free and non-corrosive Zn plating/stripping and enhances the electrochemical performance of Zn||PEDOT-V2O5 full cells. image