Effects of microstructure on the electrochemical discharge behavior of Mg-6wt%Al-1wt%Sn alloy as anode for Mg-air primary battery

The discharge performance of Mg-6wt.%Al-1wt.%Sn alloy is enhanced by hot extruding and subsequent annealing treatment. Limited dynamic recrystallization is observed during the hot extruding process and the extruded alloy exhibits the non-uniform microstructure. Subsequently, 200 °C annealing treatment effectively facilitates the precipitation of second phases and spherical Mg2Sn phases with typical sizes of 50-100 nm uniformly distribute in the Mg-Al-Sn alloy. The 200 °C annealed Mg-Al-Sn anode shows the excellent discharge performance in 3.5 wt% NaCl solution, attributed to fine Mg2Sn phases and fully recrystallized microstructure which accelerate the self-peeling of corrosion products. With air battery tests, the 200 °C annealed Mg-Al-Sn alloy is a promising anode for magnesium-air batteries.