Effect of hot rolling on the microstructure and discharge properties of Mg-1.6 wt%Hg-2 wt%Ga alloy anodes

Mg-Hg-Ga alloys are typical anode materials used in high-power seawater-activated batteries. In this work, the effect of hot rolling on the microstructure and discharge properties of Mg-1.6 wt%Hg-2wt%Ga alloy was studied. The results indicate that hot rolling refines and deforms the grains, weakens the basal texture, and facilitates the dispersive precipitation of Mg5Ga2 and nano-scaled Mg21Ga5Hg3 phases. The precipitation of secondary phases during rolling reduces the solid solubility of Hg and Ga in the Mg matrix, thus deteriorating discharge activity and thickening the discharge product film in the Mg-Hg-Ga alloy. Nevertheless, the 0.35 mm-thick hot-rolled Mg-Hg-Ga alloy exhibits an excellent corrosion resistance and high specific discharge capacity (1903 mAh g−1) during discharge at the current density of 20 mA cm−2. Therefore, the rolled Mg-Hg-Ga alloy is a promising anode material for application in low-power and long-term seawater batteries.