<p>A novel homogeneous Mg-1Bi-0.5X (X = Gd, Y, Nd, Ce, La) alloy was fabricated in this study, and its electrochemical properties as well as discharge characteristics as an anode material for primary magnesium-air batteries were systematically investigated through electrochemical tests and battery discharge experiments. The results demonstrate that the addition of Nd promotes the formation of a refined grain structure and semi-continuous network-distributed NdBi secondary phase, which significantly enhances the discharge performance. Microstructural analysis reveals that the discharge products of Mg-1Bi-0.5Nd exhibit a loose, porous morphology. This structure facilitates product exfoliation via crack propagation, thereby improving electrolyte accessibility and enhancing the anode’s discharge stability and efficiency. At a current density of 20&#xa0;mA cm⁻², the alloy achieves a specific capacity of 1492.54 mAh g⁻¹ and an anodic efficiency of 68.5%, representing a 114.1% improvement over that of the AZ31. These results highlight the superior discharge performance of the Mg-1Bi-0.5Nd anode.</p>