Performance of an Al–0.08Sn–0.08Ga–xMg alloy as an anode for Al–air batteries in alkaline electrolytes

Aluminum (Al) electrodes doped with metals, such as Sn, Ga, and Mg, were prepared by smelting to study the effects of Mg content on the properties of Al electrodes. After testing the corrosion resistance and electrochemical properties (in 4 M NaOH solution) of the Al–0.08Sn–0.08Ga–xMg alloy, the results were compared to virgin Al and an Al–Sn–Ga alloy. The battery performance was studied by constant current discharge. Scanning electron microscope and energy-dispersive X-ray analysis were used to investigate the corrosion form and discharge surface of the alloys. Results showed that the Mg–Sn and Mg–Ga phases act as corrosion centers enabling negative corrosion potential. Electrochemical test results revealed that compared with the pure Al and Al–Sn–Ga alloy, the Al–0.08Sn–0.08Ga–0.5Mg alloy not only showed a more negative potential but also showed enhanced activity. Moreover, it showed high energy density (3169.7 Wh kg−1) and improved anode efficiency (86.9 ± 0.2%) when used as an anode for an aluminum–air battery in NaOH solution.