Suppressing Zinc Dendrites via Polyamine–Zn2+ Complexation in Weakly Acidic Electrolytes (Supporting Information)

Rechargeable zinc batteries, with a theoretical capacity of 820 mAh g−1, provide advantages such as non-flammability, low cost, and environmental compatibility, but dendrite growth remains a major obstacle to long-term cycling. Here, we investigated the coordination behavior of diethylenetriamine (DETA) and triethylenetetramine (TETA) at pH 5.5 using proton nuclear magnetic resonance (1H NMR) spectroscopy, operando optical microscopy, electrochemical measurements, and scanning electron microscopy. Both ligands reversibly interact with Zn2+, yet TETA exhibits superior ability to regulate deposition and suppress dendrite growth. This advantage is attributed to more stable Zn–TETA complexation. These findings emphasize the importance of coordination stability and interfacial regulation in additive design, providing practical guidance for improving the cycling performance of aqueous zinc batteries.