Revealing the Limitation Induced by Hydroxyl in Regulating Solvation Structure of Zn²⁺ and Overcoming Challenges with Hybrid Additives towards Highly Stable Zinc Anodes

In the field of electrolyte design for aqueous zinc-ion batteries (AZIBs), additives containing hydroxyl have been demonstrated to effectively modulate the solvation structure of Zn²⁺. However, reported studies typically focus solely on the effectiveness of hydroxyl while neglecting the issues that emerge during solvation structure regulation. The strong electron-attracting capability of Zn²⁺ attracts electrons from the oxygen in hydroxyl, thereby weakening the strength of hydroxyl, the hydrogen evolution reaction (HER) is also pronounced. This work innovatively reveals the limitation of hydroxyl-containing additives and proposes a synergistic regulation strategy based on hybrid additives. Arginine with a high isoelectric point is introduced into the electrolyte system containing hydroxyl additives. The protonation effect and electrostatic attraction of arginine enable it to absorb protons at the anode released by the weakened hydroxyl, thereby compensating for the limitation of hydroxyl additives. Under the synergistic action of hybrid additives, the Zn|Zn battery achieved stable deposition/stripping for over 1200 hours under 10 mA cm⁻² and 10 mAh cm⁻². Moreover, the Zn|Cu battery cycled for over 570 hours with a high Coulombic efficiency of 99.82 %. This study presents a pioneering perspective for the further application of AZIBs.