Chiral-driven synergistic electrolyte engineering for ultrastable aqueous zinc-ion batteries

Electrolyte additive engineering is crucial for advancing aqueous zinc-ion batteries (AZIBs), yet stereochemical effects remain underexplored. This study systematically investigates the impact of L- and D-configured amino acids as electrolyte additives, uncovering unprecedented chiral-dependent effects on Zn²⁺ solvation and anode interfacial chemistry. Taking valine (Val) as a model additive, we reveal that L-Val forms a dual‑oxygen-coordinated solvation sheath with Zn²⁺, effectively reducing H₂O activity and suppressing side reactions. In contrast, D-Val forms a mono‑oxygen-coordinated complex with limited solvation structure modification. Mechanistic insights show that L-Val preferentially adsorbs onto the Zn anode via its amino (−NH₂) functional group, while outward carboxyl (-COOH) groups self-assemble into a protective layer. This architecture promotes dendrite-free Zn deposition and reversibility, achieving symmetric cell cycling stability of 5200 h (vs. 3600 h for D-Val), Zn||Cu cell Coulombic efficiency of 99.7 % over 1500 cycles, and pouch cell capacity retention of 93.2 % after 1100 cycles. These findings highlight chiral molecular engineering as a transformative strategy for electrolyte design, offering generalizable principles applicable to multivalent-ion battery systems.