Metallic silver doped vanadium pentoxide cathode for aqueous rechargeable zinc ion batteries

Recently, rechargeable aqueous zinc-ion batteries have received considerable attention in relation to large-scale energy storage, mainly because of their advantages of environmental friendliness, non-toxicity, and favorable safety. However, little researches have been conducted on the cathode materials used in zinc-ion batteries. In this work, an aqueous zinc-ion battery is constituted based on metallic silver doped vanadium pentoxide cathode, Zn(CF3SO3)2 aqueous electrolyte, and zinc anode, which exhibits excellent electrochemical performance. At a current density of 0.1 A g−1, the specific capacity of about 215 mAh g−1 was retained after 50 cycles. It also delivers long-cycle stability at 3 A g−1, which remains at 80 mAh g−1 after 700 cycles. Furthermore, the reaction mechanism is confirmed by X-ray diffraction, ex-situ Raman, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy analysis. This outstanding performance is attributed to the high conductivity of the cathode material and the vacancy exchange mechanism of Zn2+/Ag+. This research shows metallic silver doped vanadium pentoxide cathode which could be considered a promising cathode material for aqueous zinc-ion batteries.