Designing Cost-Effective Molecule-Substitution-Induced Anchoring Additives to Enable Stable Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are considered among the most promising energy storage systems because of their low cost, high safety, and high theoretical capacity. However, challenges including Zn²⁺ desolvation, side reactions, and dendritic growth significantly hinder their rate capability and cycling stability. In this study, we propose a molecule-substitution-induced anchoring strategy by introducing kojic acid molecules with carbon-based (C═O) and hydroxyl (C-OH) groups to modulate the Zn²⁺ solvation structure, lower the desolvation activation energy, and effectively suppress undesirable side reactions. More importantly, its pyranone ring (C-O-C) can anchor onto the Zn surface to form an adsorption layer, which induces the uniform deposition of Zn²⁺ ions and consequently suppresses dendrite formation. At a current density of 1 mA cm⁻² and an areal capacity of 1 mAh cm⁻², the symmetric cell demonstrated an ultralong lifespan of 2800 h and a high Coulombic efficiency of 99.72%. Furthermore, the assembled Zn||δ-MnO₂ full cell had a capacity retention of 95% after 1500 cycles at 3 A g⁻¹. Even at an elevated temperature of 50 °C, the cell retained a capacity of 197.9 mAh g⁻¹ after 200 cycles.