On mechanism of corrosion inhibition of green inhibitor polyvinyl alcohol in aluminum-air batteries

Aluminum-air batteries (AABs) are considered as a promising green energy source owing to high energy density, light weight, and non-pollution. However, hydrogen evolution reaction (HER) of the anode presents a challenge to their further developments. In this study, the influence of polyvinyl alcohol (PVA) as an inhibitor on the inhibition and battery performance is investigated by experiments, molecular dynamics (MD) simulations, and density functional theory (DFT). It is demonstrated that, with addition of 1 % PVA1099, the inhibition efficiency increased by 60.44 %. Meanwhile, the battery performance is significantly enhanced. The addition of 1 % PVA1099 results in a capacity density of 1600.0 mAh g⁻¹ for the AAB cell, which is 2.3 times that of the 4 M NaOH. The results of the MD and DFT simulations indicate that PVA molecules are capable of adsorbing Al surface, forming a film on the surface of Al anode; simultaneously adsorbing H₂O molecules, giving rise to a stronger H-bond effect. This work sheds light on the mechanism underlying inhibition performance of PVA molecules, suggesting that PVA with long -OH chains is an effective inhibitor in ABBs.