Synchronous regulation of V2O5 cathode and Zn anode using sodium gluconate as an additive for long-life aqueous zinc-ion batteries

Sodium gluconate improves aqueous zinc-ion battery performance by in situ insertion of Na + in the V 2 O 5 cathode for stability, while disrupting the solvated structure of Zn 2+ at the anode to inhibit dendrite formation and corrosion. Aqueous zinc-ion batteries (AZIBs) are gaining attention owing to their affordability, high safety, and high energy density, making them a promising solution for large-scale energy storage. However, their performance is hampered by the instability of both the anode-electrolyte interface and the cathode-electrolyte interface. The use of sodium gluconate (SG), an organic sodium salt with multiple hydroxyl groups, as an electrolyte additive is suggested. Experimental and theoretical analyses demonstrate that Na + from SG can intercalate and deintercalate within the associated V 2 O 5 cathode during in situ electrochemical processes. This action supports the layered structure of V 2 O 5 , prevents structural collapse and phase transitions, and enhances Zn 2+ diffusion kinetics. Additionally, the gluconate anion disrupts the original Zn 2+ solvation structure, mitigates water-induced side reactions, and suppresses Zn dendrite growth. The synchronous regulation of both the V 2 O 5 cathode and Zn anode by the SG additive leads to considerable performance improvements. Zn||Zn symmetric batteries demonstrate a cycle life exceeding 2800 h at 0.5 mA cm −2 and 1 mAh cm −2 . In Zn||V 2 O 5 full batteries, a high specific capacity of 288.92 mAh g −1 and capacity retention of 82.29% are maintained over 1000 cycles at a current density of 2 A g −1 . This multifunctional additive strategy offers a new pathway for the practical application of AZIBs.