Investigation of corrosion and electrochemical oxidation behaviors of Al–Zn–Sn and Al–Zn–Bi alloy electrodes in alkaline electrolytes

Investigating the corrosion and anodic oxidation behaviors of aluminum-based alloys in alkaline electrolytes can aid in the development of long-lasting aluminum-air batteries. The impact of adding tin and bismuth to Al-Zn alloy electrodes was investigated in KOH electrolytes. It was found that Al-Zn and Al-Zn-Sn electrodes had higher negative corrosion potentials and lower corrosion rates compared to Al electrodes. Tin played a role in activating Al-Zn by reducing the electrode passivation during anodic polarization. The functioning mechanisms of Zn and Sn in Al-Zn-Sn electrodes are studied by modifying the electrolytes with zincate - generated by ZnO addition - and stannate ions. Zincate ions inhibit Al and Al-Zn electrode corrosion. However, while stannate ions in electrolytes activate Al electrode corrosion, they inhibit Al-Zn electrode corrosion. Bismuth is not an activator choice for Al-Zn alloy because Bi intensifies the electrode passivation during anodic polarization. • Corrosion and anodic oxidation of Al-Zn-Sn and Al-Zn-Bi electrodes in alkaline electrolytes. • Tin is an activator for Al-Zn electrodes, but Bi augments passivation. • Stannate ions in electrolytes activate Al electrodes but fail to activate Al-Zn electrodes. • Different Sn-induced activation processes for Al and Al-Zn electrodes.