Modulated bonding interaction in propanediol electrolytes toward stable aqueous zinc-ion batteries

Abstract

Aqueous Zn-based batteries are promising energy storage technology due to their low cost and high safety. However, the solvation structure of electrolyte leads to dendrite growth, parasitic reactions, and poor low-temperature properties, limiting their practical application. Here, we report 1,2-propanediol (PG) electrolyte with a modulated solvation structure, which can suppress Zn dendrite growth and parasitic reactions. PG can break the interaction between H2O molecules and the interaction between H2O and Zn2+ due to the higher electron density of O and higher Gutmann donor number of PG than those of H2O, which increase the H-O covalent bond strength, decrease the water activity and freezing point, and change the solvation structure of Zn2+. As a result, the battery exhibits high cycling stability (Zn//Zn battery cycle over 1000 h), high reversibility (Coulombic efficiency of 98.9%), high capacity properties (specific capacity of 225 mA h g−1 at 5 A g−1, and capacity retention of 92.6% for 5000 cycles), and excellent anti-freezing properties (specific capacity of 190 mA h g−1 at −20°C over 500 cycles). This work provides a promising strategy for the development of highperformance aqueous zinc-ion batteries.