Glycine/carbon quantum dot dual modulation cooperatively stabilizing Zn anode interfaces

Abstract

Aqueous zinc-ion battery systems (AZIBs) demonstrate significant potential for grid-scale energy storage applications. Nevertheless, the limited electrochemical durability of zinc electrodes, primarily due to parasitic reactions in aqueous electrolytes and uncontrolled dendrite formation, poses substantial challenges. In this work, double-effect glycine (Gly)/carbon quantum dot (CQD) hybrid additives were explored to realize an electrochemically stable Zn anode with high reversibility. Gly can regulate Zn²⁺ solvation sheath reconstruction, whereas hydrophilic nanocrystalline CQDs improve the kinetics of Zn²⁺ plating/stripping and provide the preferential nucleation domains for epitaxial zinc electrodeposition. Due to this dual effect, Zn//Zn symmetric cells demonstrate unprecedented electrochemical robustness, sustaining stable cycling for over 2000 h (83 days) under demanding operational conditions (1 mA cm⁻², 1 mAh cm⁻²) while exhibiting remarkable rate capability. Zn//Cu asymmetric cells demonstrate an exceptional average coulombic efficiency (CE) of 99.02% under standard plating conditions (1 mA cm⁻², 0.5 mAh cm⁻²).