Influence of Ba micro-alloying on electrochemical and discharge behaviors of Mg-Al anodes for mg-air primary battery

Herein, we report a new strategy of Ba micro-alloying to enhance the anode properties of the Mg-air primary battery anode materials. The influence of Ba micro-alloying on electrochemical behavior, corrosion resistance, and discharge properties of Mg-6Al anodes in Mg-air batteries was specifically investigated. Ba micro-alloying markedly improved the corrosion resistance of Mg-6Al alloys, which was due to the grain refinement and the inhibition of the cathodic hydrogen evolution reaction. However, when Ba content reached 0.7 wt.%, the coarse Al13Ba7 phase accelerated the galvanic corrosion and increased the corrosion rate. Moreover, the Mg-6Al-0.4Ba anode had the optimal discharge capacity and anode efficiency at 20 mA cm(-2) with 893.66 mAh g(-1) and 39.36%, respectively, which was 22.1% and 22.4% higher than that of the Mg-6Al anode. The enrichment of discharge properties was attributed to the refinement of grains and the improvement of the self-corrosion resistance. In addition, Ba micro-alloying improved the absorption capacity of the anode, which was conducive to the self-exfoliation of the discharge products. The Novelty Statement This paper prepared the Mg-6Al-xBa anodes by Ba micro-alloying to enhance the discharge properties. The generation of Al13Ba7 phase and the refinement of grains caused by Ba addition reduced the corrosion rate and increased the discharge capacity and anodic efficiency of Mg-6Al alloy. Thus, Ba micro-alloying can improve the corrosion resistance and discharge performance of Mg-6Al alloy.