Discharge Behavior and Mechanism of Solid-Solution-Treated Alloy Anodes for Magnesium–Air Batteries

This work studies the properties of magnesium (Mg) alloy–air batteries with solution-treated alloys. Both Zn and Sn are eco-friendly elements with high solubilities in Mg. The effect of solid-solution Zn and Sn on Mg alloys has been studied as the anode material in Mg–air batteries. The preferred corrosion orientation extending along the (0001) basal plane has been found in pure Mg and Mg alloy anodes. Alloying Sn and Zn can alleviate the preferred corrosion during discharge. The main discharge product is Mg(OH)2, containing two kinds of structures─the microsized products close to the anode have a high content of ZnO/Zn(OH)2 and SnO1–2 oxide and the nanosized products close to the cathode. Solution-treated Mg–2 wt % Zn–3 wt % Sn alloy anodes have outstanding battery performance with a high energy density of 1594 mWh g–1 at 5 mA cm–2, an anodic efficiency of 60.35%, and a specific density of 1291 mAh g–1 at 10 mA cm–2.