Gel polymer electrolyte based on deep eutectic solvent in flexible Zn-air batteries enables dendrite-free Zn anode

Flexible Zn-air batteries (FZABs) are competitive candidates for wearable energy storage devices due to their high theoretical energy density, high safety and low cost. Various alkaline gel polymer electrolytes (GPEs) greatly reduce the operating time of the ZABs, which is prone to water loss and corrosion of the Zn anode. Therefore, one of the effective strategies is to prepare non-alkaline GPEs with excellent thermal stability. Herein, a novel acetamide (C2H5NO)/ZnCl2/H2O ternary deep eutectic solvent (DES) is developed. The GPE (named PAA-DES is synthesized in one step by introducing PAA polymer network into deep eutectic solvent (DES), which is applied to FZABs. H2O in the solvated structure of Zn2+ is replaced by C2H5NO, and is controlled through hydrogen bonding. The obtained PAA-DES shows excellent tensile properties and electrolyte retention rate, and effectively inhibits dendrite growth of Zn anode. ZABs based on PAA-DES have good bending ability, which can operate for nearly 1000 h.