Eutectic Crystallization Activates Solid-State Zinc-Ion Conduction

Solid-state zinc (Zn) batteries offer new desirable candidate for emerging applications sensitive to volume, safety and cost. However, current solid polymeric or ceramic electrolyte structures remain poorly conductive for the divalent Zn2+, especially at room temperature. Constructing a heterogeneous interface which allows Zn2+ percolation is a viable option, but this is rarely involved in multivalent systems. Herein, we split a new path to construct solid  Zn2+-ion conductor via inducing crystallization of tailored eutectic liquids formed by organic Zn salts and bipolar ligands. High-entropy eutectic-networks avail to weaken the ion-association and form interfacial Zn2+ percolated channels on the nucleator surfaces, resulting in a solid crystal with exceptional selectivity for Zn2+ transport (tZn2+ = 0.64) and appreciable Zn2+ conductivity (σZn2+ = 3.84 × 10-5 S cm-1 at 30 °C, over 2 orders of magnitude conventional polymers), and finally enabling practical ambient-temperature Zn/V2O5 metal solid cells. This design principle leveraged by the eutectic solidification affords new insights on the multivalent solid electrochemistry suffering from slow ion migration.