Computational design of ductile magnesium alloy anodes for magnesium ion batteries

The main advantage of Mg‐ion batteries over other metal‐ion counterparts is its ability to work with a pure metallic anode, achieving a very high specific capacity. Unfortunately, pure Mg is hard to machine due to its brittleness, making it extremely difficult to produce foils that are thin enough for practical battery applications. Alloying Mg with small amounts of doping elements can enhance its ductility. However, care should be given to ensure that the dopants do not interfere with the electrochemical process of plating and stripping of Mg from the anode during battery operation. Dopants should prefer to be in bulk or at a stacking fault rather than migrating to the surface to meet this requirement. In this work, we carried out a computational screening of 34 dopants that are reported to reduce Mg brittleness to check which of them energetically prefers to stay in bulk. We found that only 12 out of the 34 meet such a criterion. Y and Nd, two of the main dopants in the WE43 commercial alloys, are among the 12 beneficial doping elements, which presents a practical avenue for the exploration for superior Mg‐ion battery anode material.