EDTA-3Na optimized electrolyte enables reversible zinc storage in VO2//Zn full cells

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the potential alternatives for lithium-ion batteries. Vanadium-based oxides as cathode materials have aroused increasing attention because of their advantages, such as low cost and high specific capacity. But its rapid capacity decay prompted researchers to explore various modified techniques. Herein, an electrolyte modification strategy by introducing acid trisodium salt (EDTA-3Na) additive to 2 M ZnSO4 solution is developed to stimulate high reversible zinc storage. The desolvation effect of EDTA-3Na in the electrolyte optimizes the zinc deposition behavior and inhibits the formation of zinc dendrites, which could reduce the resistance of the VO2//Zn full cells and accelerate the reaction kinetics of the cathode. The VO2//Zn full cells can present a high zinc storage capability of 281.5 mAh g(-1) at a high current density of 5 A g(-1) after 1000 cycles and deliver prominent rate performance of 403.6, 373.5, 343.1, and 297.6 mAh g(-1) at 1, 2, 4, and 8 A g(-1) respectively.