Abstract:

A widely used oxyanion corrosion inhibitor (Li₂CrO₄) was used as electrolyte additive (3.5 wt% NaCl solution was used as electrolyte solution) for Mg-air battery. The potentiodynamic polarization tests showed that the presence of 0.1 wt% Li₂CrO₄ in the NaCl electrolyte reduced enormously the corrosion current density of the tested AZ31 Mg alloys. According to the intermittent discharge tests, the use of 0.1 wt% Li₂CrO₄ as electrolyte additive increased the anode efficiency of the Mg-air battery by 28.4%. The addition of 0.1 wt% Li₂CrO₄ reduced the anode self-corrosion rate of the battery in the intermittent stage effectively. The product film after discharge was observed by scanning electron microscope, and the Mg-air battery containing 0.1 wt% Li₂CrO₄ has a loose product film, which is beneficial to its discharge performance. So using Li₂CrO₄ as electrolyte additive could improve the intermittent discharge performance of Mg-air battery. And the use of oxyanion corrosion inhibitor as electrolyte additive may be an excellent way to improve the intermittent discharge performance of Mg-air battery.

Key words: Mg alloys, Corrosion, Mg-air battery, Intermittent discharge performance, Anode efficiency