Highly Reversible Zinc-Ion Battery Enabled by Suppressing Vanadium Dissolution through Inorganic Zn2+ Conductor Electrolyte

Abstract Rapid capacity degradation under small current density limits its development of vanadium-based aqueous zinc-ion batteries (ZIBs). Moreover, free water molecules in aqueous electrolytes tend to instigate side reactions at electrode surfaces. It is difficult to balance trade-offs between high kinetic ability and severe parasitic reactions initiated by free water, therefore, we report an inorganic Zn2+ conductor electrolyte (ZHAP-Zn) with less water to conceive a type of solid-liquid hybrid Zn2+ ion transportation channels for ZIBs. With a high transference number (t+ ~0.75), it enables a superior stability at 1 A g-1 (91% retention over 500 cycles) and even under a small current density of 0.2 A g-1 for Zn/NH4V4O10 batteries by means of inhibiting the dissolution and shuttle effect of vanadium elements, as well as the long-time storage. The higher capacity retention is also confirmed in the V2O5-based ZIBs. For zinc metal anode, ZHAP-Zn enables dendrite-free and hydrogen-free plating/stripping over 2000 h at 0.5 mA cm-2. The unique strategy on electrolyte design plays an important role in solving the problems facing by vanadium-based ZIBs.