Discharge properties of Mg-Zn-Ca-In alloys as anodes for primary Mg-air batteries

Abstract

The synergistic enhancement of voltage and efficiency remains a critical challenge in the development of high-energy-density magnesium–air batteries. In this study, a novel Mg-1Zn-1Ca-1.5In anode was developed, demonstrating superior performance with anodic efficiency of 65.74 %, discharge voltage of 1.38 V, and specific energy density of 1953.01 ± 132.9 mWh g⁻¹ at 10 mA cm⁻². To understand the underlying mechanisms, synergistic strategies contributing to the concurrent enhancement of both voltage and efficiency were systematically investigated. The presence of the (Mg, In)₂Ca phase promotes the primary dissolution and subsequent formation of the discharge products, effectively facilitating the transfer of hydrogen evolution sites from the secondary phase to the α-Mg matrix. Meanwhile, the incorporation of In into the α-Mg matrix significantly suppresses the hydrogen evolution reaction, thereby enhancing anodic efficiency. Additionally, the negative shift of the self-corrosion potential and the formation of a thinner discharge product layer further improve the discharge voltage. This study provides valuable insights into the rational design of magnesium alloy anodes with simultaneously high efficiency and voltage, offering a promising pathway toward the development of next-generation Mg–air batteries.