Effect of Gd content on the discharge and electrochemical behaviors of the magnesium alloy AZ31 as an anode for Mg-air battery

In this research, cast magnesium alloys AZ31-xGd are assessed as anode material candidates for primary Mg-air batteries. The effects of Gd content in the microstructure, discharge behavior and electrochemical properties of cast AZ31 as an anode are studied through microstructure characterization, electrochemical measurements and battery discharge tests. Results indicate that the introduction of Gd can refine α-Mg grains. The discharge and electrochemical properties of magnesium alloys are improved by optimizing its composition. We confirm that the Al2Gd can restrain the kinetics of hydrogen evolution reaction. The acicular structure can connect the magnesium alloy matrix and reduce the chunk spalling. The data suggest that AZ31-5.8Gd alloy has the best self-corrosion resistance performance and discharge behavior among all prepared AZ31-xGd alloys. AZ31-5.8Gd can output a high specific capacity of 1411.8 mAh g−1 and a high energy density of 1153 mWh g−1 at the current density of 40 mA cm−2. The anode efficiency can reach up to 63.21%. The addition of Gd properly can optimize magnesium alloy microstructure and improve the discharge performance.