Electromechanical behavior of dual network polyethylene oxide/polyvinyl alcohol composite hydrogel electrolyte for metal-air battery: A DFT and molecular dynamics approach.

Hydrogel electrolytes for metal-air batteries have recently gained attention. However, absence of well-optimized data on their structure-property relationship at the atomic scale limits their practical application. Density functional theory and molecular dynamics techniques were used to investigate the electronic, energetic, transport, and mechanical properties of polyethylene oxide (PEO)/polyvinyl alcohol (PVA) hydrogel electrolytes. Frontier Molecular Orbitals of the PEO molecular chain exhibited its electron transfer potential, and a negative band gap confirmed its stability. The highest binding energy was 374.7 × 10¹⁰ kcal/mol at 343 K. Greater binding energy of the order 0.6 > 0.8 > 1.0 > 0.4 > 0.2 > 1.2 was achieved with optimal value of 0.6 wt% crosslinker concentration. Mean square displacement of potassium ions (K⁺) remained constant with time while diffusion coefficient exhibited a linear correlation with temperatures. Hydrogel composition had varying effects on elastic moduli. The structure-property correlation of PEO and PVA is extremely beneficial in development of enhanced quasi-solid polymer electrolytes for metal-air batteries.