Computational Design of Ductile Magnesium Alloy Anodes for Magnesium Batteries

Abstract

The main advantage of Mg batteries over other metal 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 battery anode material.

Roadmap on multivalent batteries

“…On the other hand, another challenge is the poor mechanical properties of pure Mg foils caused by its limited intrinsic ductility [102], brittleness and mechanical weakness, especially for ultrathin foils (<100 µm) [103]. However, to obtain high specific energy Mg batteries, it is mandatory to use thin Mg metal foils anodes (15 µm), by means of Mg alloys [103][104][105].…”

A practical perspective on the potential of rechargeable Mg batteries

“…81 However, a recent computational study focused on cast alloys, which have good processibility and thus scalability, reported that only a few of the studied elements were beneficial for the electrochemical process of plating and stripping. 100 Besides, Yang et al collected several studies which reported the influence of microstructure and composition of Mg alloys on their mechanical properties, ductility, and strength. These kinds of properties might profoundly affect the performance of different alloy anode materials for RMB.…”

Magnesium: properties and rich chemistry for new material synthesis and energy applications

“…However, the poor ductility of the pure Mg metal makes it challenging to produce very thin Mg electrodes. 247,248 Maddegalla et al demonstrated the viability of manufacturing ultrathin Mg anodes (B25 mm thickness) in electrochemical cells by using AZ31 Mg alloys (3 wt% for Al, 1 wt% for Zn, and 96 wt% for Mg). 249 Despite the use of the alloyed anode, the AZ31 Mg alloy thin foil anodes exhibited electrochemical behaviours comparable to pure Mg foil anode (B100 mm thickness) during the Mg stripping and deposition process.…”