Performance of Mg–9Al–1In Alloy as Anodes for Mg-Air Batteries in 3.5 wt% NaCl Solutions

Abstract

Mg alloys are promising anode materials for metal-air batteries because of their high theoretical voltages, high current capacities, and environmental friendliness. In this paper, the discharge performance of Mg–9Al–1In (AI91) alloys as anodes for Mg-air batteries is investigated by electrochemical techniques and compared with anodes of Mg–9Al (A9) and Mg–9Al–1Zn (AZ91) alloys. The electrochemical discharge behavior of these anodes in 3.5 wt% NaCl solutions was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The microstructures and the corroded surfaces of the anodes were investigated by scanning electron microscopy (SEM) and electron probe microscope analysis (EPMA). The performance of Mg-air batteries based on these alloy anodes was studied by constant current discharge. The results indicate that the AI91 alloy exhibits a refined microstructure and a better discharge activity than the A9 alloy and AZ91 alloy. Mg-air batteries based on AI91 anodes have an average discharge potential of 1.2157 V at a discharge current density of 10 mA cm−2, which is higher than that of batteries with A9 and AZ91 anodes. In addition, they possess the highest capacity density (1886.8 mAh g−1) and power density (22.428 mW cm−2).