Effects of Heat Treatment on the Discharge Behavior of Mg-6wt.%Al-1wt.%Sn Alloy as Anode For Magnesium-Air Batteries

Mg-6wt.%Al-1wt.%Sn alloys under different conditions are prepared. Primary magnesium-air batteries are assembled using such experimental Mg-Al-Sn alloys as anodes. The discharge behaviors of different alloys are investigated in 3.5 wt.% NaCl solution. The results show that the solution treatment can facilitate the homogeneous distribution of alloy elements and reduce the accumulation of discharge products. The magnesium-air battery based on the solution-treated Mg-Al-Sn anode presents higher operating voltage and more stable discharge process than those on the as-cast and the aged ones. Although the solution treatment cannot effectively improve the capacity density and the anodic efficiency of the experimental Mg-Al-Sn alloy, it is an effective approach to increasing the power and the energy density during discharge process. Especially at the applied current density of 30 mA cm⁻² for 5 h, the solution-treated anode supplies 1.212 V average operating voltage, the anode energy density reaches 1527.2 mWhg⁻¹, while the cast one is 1481.3 mWhg⁻¹ and the aged one is 1478.8 mWhg⁻¹.