Mg batteries have received increasing attention mainly because of their high volumetric capacity (3832 mAhcm−3). In order to form type NO.5 cell packing for Magnesium battery the finite element simulation by Deform 3D was carried out. Then backward extrusion was conducted on an AZ31 magnesium alloy at 300°C. The results show that battery cell packing with the wall of 0.35 mm can be formed through backward extrusion with an AZ31 Mg alloys. A significant grain size refining was resulted from hot BE, however, the microstructure in different positions of the Mg cell packing was inhomogeneous. At bottom of the packing, the microstructure was formed by equiaxial and relatively coarse grains. The wall of the Mg cell packing was made of much finer grains.

In this study, an Mg-air battery based on air cathode with different content of Na2SO4 was prepared to study the effect of Na2SO4 on the performance of Mg-air battery. The electrochemical performance of the air cathode was studied by potentiodynamic polarization and electrochemical impedance spectroscopy. The results indicated that the electrochemical activity of the electrode enhanced with the increasing Na2SO4. The discharge performance of the battery was investigated by constant-current discharge test, and the results showed that the discharge potential of the battery also improved with the increasing of Na2SO4. However, the forming of air cathode became difficult gradually with the increasing content of Na2SO4. What is worse, the oversize pore produced in the moisture barrier when the content of Na2SO4 was too high and the moisture barrier would lose resistance to water. So the content of Na2SO4 should not be too high.