AZ31 Magnesium Alloy Foils as Thin Anodes for Rechargeable Magnesium Batteries

In recent decades, rechargeable Mg batteries (RMBs) technologies have attracted much attention because the use of thin Mg foil anodes may enable development of high-energy-density batteries. One of the most critical challenges for RMBs is finding suitable electrolyte solutions that enable efficient and reversible Mg cells operation. Most RMB studies concentrate on the development of novel electrolyte systems, while only few studies have focused on the practical feasibility of using pure metallic Mg as the anode material. Pure Mg metal anodes have been demonstrated to be useful in studying the fundamentals of nonaqueous Mg electrochemistry. However, pure Mg metal may not be suitable for mass production of ultrathin foils (<100 microns) due to its limited ductility. The metals industry overcomes this problem by using ductile Mg alloys. Herein, the feasibility of processing ultrathin Mg anodes in electrochemical cells was demonstrated by using AZ31 Mg alloys (3 % Al; 1 % Zn). Thin-film Mg AZ31 anodes presented reversible Mg dissolution and deposition behavior in complex ethereal Mg electrolytes solutions that was comparable to that of pure Mg foils. Moreover, it was demonstrated that secondary Mg battery prototypes comprising ultrathin AZ31 Mg alloy anodes (approximate to 25 mu m thick) and MgxMo6S8 Chevrel-phase cathodes exhibited cycling performance equal to that of similar cells containing thicker pure Mg foil anodes. The possibility of using ultrathin processable Mg metal anodes is an important step in the realization of rechargeable Mg batteries.

Automated summary

Rechargeable magnesium batteries have attracted attention due to the potential for high-energy-density batteries using thin magnesium foil anodes. The main challenge lies in finding suitable electrolyte solutions for efficient and reversible operation. While most studies focus on developing novel electrolyte systems, there has been progress in using ductile magnesium alloys for processing ultrathin magnesium anodes in electrochemical cells, showing comparable performance to pure magnesium foils. This advancement is a key step towards realizing rechargeable magnesium batteries.