AS61 Magnesium Alloy with Nano-Scale Mg2Sn Phase as a Novel Anode for Primary Aqueous Magnesium Battery

A novel AS61 magnesium alloy is prepared via the small-hole confinement of liquid alloy by using a thick-walled copper mould. This facile method gives rise to distinct grain refinement and dispersed second phases such as nano-scale Mg2Sn (12.54 3.35 nm). Benefiting from the unique microstructure, the AS61 shows enhanced anode performance when adopted for primary aqueous battery, as compared with that using the anode of the same composition fabricated via a common iron mould during melting and casting. The Mg-air battery with the novel AS61 anode provides a high voltage of 1.269 V at 10 mA cm−2; its anodic efficiency at 10 mA cm−2 reaches 78.4%, which is higher than lots of other types of magnesium anodes. Moreover, the discharge mechanism of AS61 is also unravelled based on electrochemical response and microstructure characterization.