Effects of Zn/Ca Alloying on the Second Phase, Corrosion Behavior, and Mg–Air Battery Anodic Performance of Mg–1Sn‐Based Alloys

Abstract

To improve the corrosion behavior and discharge performance of Mg–1Sn‐based Mg–air battery anodes, Zn/Ca alloying elements are added in the alloys to modify the type and morphology of the formed second phases. Scanning electron microscope is used to observe the microstructure, and X‐ray diffraction is used to identify the phases formed. Immersion, electrochemistry techniques, and Mg–air battery tests are used to characterize the corrosion and discharge performance of the alloys. The results indicate that the addition of Ca rather than Zn has better effects in improving the corrosion resistance and discharge performance of Mg–1Sn‐based alloys. The second‐phase combination improves the corrosion resistance and electrochemical activity of Mg–1Sn‐based alloys in the following order: Mg2Ca and CaMgSn phases (Mg–1Sn–1Ca alloy) > Ca2Mg6Zn3 and CaMgSn phases (Mg–1Sn–1Zn–1Ca alloy) > the net‐shape Mg4Zn7 + Mg2Sn phases (Mg–1Sn–1Zn alloy) > Mg2Sn phase (Mg–1Sn alloy). In addition, Mg–1Sn–1Zn–1Ca alloy exhibits the highest anodic efficiency, specific capacity, and specific energy among four alloys, i.e., 54.3 , 1197.6 mA h g−1, and 1366.1 mW h g−1, respectively, at a current density of 20 mA cm−2.