Functional-Group Synergy Regulates Dynamic Hydrogen-Bond for High-Rate and Wide-Temperature Zinc Deep Eutectic...

Zinc deep eutectic electrolytes (DEEs) have garnered increasing interest due to their unique physicochemical properties. However, simultaneously achieving high-rate capability and wide-temperature operation remains challenging because strong solvent-ion interactions increase both viscosity and desolvation barriers. Here, three model DEEs were constructed using propionamide, N-methylacetamide, and methylurea to systematically elucidate the roles of C═O, NH, and NH₂ functional groups in regulating salt dissociation and hydrogen-bond networks. Comparative studies reveal that the cooperative C═O/NH groups govern efficient Zn-salt dissociation, whereas the additional NH₂ group transforms a relatively rigid hydrogen-bond network into a dynamically reconfigurable one. The resulting enhanced dynamic hydrogen-bond exchange continuously reconstructs the Zn²⁺ solvation environment, lowers the desolvation barrier, increases ligand participation in the primary solvation sheath, and promotes the formation of a robust N/Cl-rich hybrid interphase. Consequently, the optimized ZCMI enables highly reversible Zn plating/stripping from -40°C to 60°C, sustains stable cycling for over 8000 h at -40°C, and supports current densities up to 10.0 mA·cm^-2. Zn||PANI full cells exhibit excellent rate capability, retain 96% of their initial capacity after 1200 cycles at -40°C, and operate stably at 60°C. These findings establish dynamic hydrogen-bonding as a key descriptor governing solvation chemistry in zinc DEEs.