Multi-elemental Synergistic Optimization of Mg-Ge-In-Zn as a Promising Anode for Primary Mg-Air Batteries

In this work, a strategy was employed to construct the microstructure of Mg-Ge-In-Zn alloys through the utilization of Ge, In, and Zn elements with varying solid solubility in magnesium. Utilizing a range of detection techniques, it was discovered that the microstructure of Mg-Ge-In-Zn alloys primarily comprises two secondary phases: Mg₂Ge and MgZn. Compared to pure magnesium and Mg-Ge-In alloys, Mg-Ge-In-Zn alloys exhibit superior corrosion resistance, higher and more stable discharge voltages, as well as enhanced anode utilization efficiency. Furthermore, the discharge process of Mg-Ge-In-Zn alloys encompasses several stages. Initially, the Mg₂Ge phase activates the adjacent regions in contact with it. Subsequently, once the Mg₂Ge phase detaches from the neighboring matrix, the MgZn phase becomes the primary contributor, maintaining the discharge behavior. Finally, newly exposed Mg₂Ge and MgZn phases generate discharge active sites, further activating the alloy surface.