Effect of Multi-Pass Rolling on the Performance of AZ31 Magnesium Alloy Anode in Mg-Air Battery

In this work, the influence of rolling passes on microstructure, corrosion behavior, electrochemical performance, and battery performance of AZ31 magnesium alloy was studied. The experimental results show that the grain size decreases first and then increases with rolling passes. Among them, the grain size of three passes rolled sample is the smallest, while the grain size of the four passes rolled sample is obviously refined and evenly distributed, accompanied by a small number of twins. Therefore, it exhibits more muscular discharge activity. In addition, the corrosion products of the four passes rolled samples are distributed loosely and evenly on the surface during immersion, which is easy to fall off, thus reducing the polarization. The surface of the discharged four passes rolled sample is flat, indicating that the dissolution is uniform, conducive to promoting the self-peeling of discharge products. The results show that the samples with four passes of rolling have high electrochemical activity and anode efficiency. The average cell voltage and anodic efficiency of the four passes rolled anode for Mg-air battery within 5 h at 10 mA cm-2 were 1.065 V and 56.4%, respectively. Therefore, the electrochemical performance of the four passes rolled sample is the best, and the process is more suitable for preparing magnesium alloy anode plate.