Engineering water-lean solvation structure to modulate interfacial chemistry for high-performance aqueous zinc-ion...

The stability and reversibility of aqueous zinc-ion batteries (AZIBs) are greatly restricted by the water-induced side reactions. Herein, N-methyl-d-glucamine (MGA) is devoted to modulating the interfacial microenvironment of the Zn anode to improve its stability. Thanks to the polyhydroxy and a methylamino structure, MGA molecules can effectively substitute three water molecules that originally coordinated with the Zn²⁺ ions by strengthened ion-dipole interaction, thus forming a water-lean primary solvation sheath of Zn²⁺ ions. Consequently, through a shielding effect, the interfacial side reactions are effectively suppressed. Additionally, the oxygen/nitrogen-containing groups on the MGA molecules show high interfacial affinity with the Zn anode, which help to repel nearby water molecules and guide Zn²⁺ uniform diffusion, thus facilitating the reversible Zn deposition. Therefore, with these merits, the Zn//Zn symmetric cells endow high cyclic stability exceeding 1500 h at 1 mA cm^-2 with 0.5 mAh cm^-2, and the Zn//Ti asymmetric cells present the boosted and stable coulombic efficiency. Subsequently, the Zn//MnO₂ full cells with MGA additive also deliver improved energy storage performance, including increased capacity, extended cycle stability, and suppressed self-discharge processes. This work provides a broad prospect for the practical application of electrolyte additives.