The influence of Ga alloying on Mg-Al-Zn alloys as anode material for Mg-air primary batteries

This paper investigates the microstructure, corrosion, electrochemical behavior, and the discharge performance of Gallium (Ga) alloyed Mg-Al-Zn alloys using the gravimetric method, electrochemical measurements, and battery test. The average grain size of AZ80–2.5Ga (Mg-8Al-0.5Zn-2.5Ga alloy) is 36% smaller than that of AZ80 (Mg-8Al-0.5 Zn alloy). The number and size of the Mg17Al12 phase particles are smaller and more homogeneously distributed. Ga reduces the self-corrosion rate, increases the electrochemical activity and the discharge performance. The grain refinement generates many grain boundaries on the surface and promotes discharge performance. The decrease of the self-corrosion rate is attributed to the suppression of the protective film that inhibits the anode consumption. The AZ80–2.5Ga anode has the optimal discharge capacity of 1437 mAh g− 1 and anode efficiency of 61% at 50 mA cm−2, which are 25% and 29% higher than for the AZ80 anode.