Electrochemical Reactivity of Magnesium Ions with Sn-Based Binary Alloys (Cu-Sn, Pb-Sn, and In-Sn)

We explored tin (Sn) alloys (Cu-Sn, In-Sn, Pb-Sn) as possible candidates for negative electrode materials of magnesium ion secondary batteries. Cyclic voltammograms revealed that In-Sn, Pb-Sn, and elemental Sn are active against Mg insertion and desertion at room temperature in a Grignard reagent, while Cu-Sn intermetallics are considerably inactive. Moreover, more than ten times of reversible peak currents were obtained for In-Sn and Pb-Sn alloys compared to pure Sn, suggesting the low-melting-point alloys enable the faster diffusion of Mg 2+ ions.