Probing corrosion protective mechanism of an amide derivative additive on anode for enhanced alkaline Al-air battery performance

Screening green corrosion inhibitors to prevent Al anode corrosion is essential for the development of high-performance Al-air batteries. This paper explores the potential of amide derivative, thiobenzamide (TBA), as the corrosion inhibitor for Al anode, and provides a universal and preferred option for improving Al-air batteries. An array of techniques were employed to probe the inhibition effect of TBA for Al-air battery in 4 M NaOH electrolyte. It is encouraging that TBA as a mixed-type corrosion inhibitor reached the inhibition efficiency of 67.8 % at an optimum addition of 0.07 M, and the specific capacity of Al-air battery dramatically increased from 461.9 mAh·g−1 (for the uninhibited system) to 1532.6 mAh·g−1 (for the TBA added system). The results of X-ray photoelectron spectroscopy (XPS) combined with ab initio molecular dynamics (AIMD) confirm that TBA can be adsorbed on the surface of Al to form a protective film, thus preventing the hydrogen evolution self-corrosion of Al anode. Herein the adsorption behavior occurred mainly through the Al–S–Al and N–Al bonding interaction between S/N atoms in TBA and Al atoms on Al surface based on the investigation of coordination numbers. The computational modeling analysis has revealed an electrolyte regulation way to improve the performance of Al-air batteries in alkaline medium.