High stability In–Sn–Bi multi-element alloy anode for Mg ion batteries

In this work, the electrochemical properties of micron In–Sn–Bi alloy electrodes for rechargeable magnesium batteries (RMBs) are evaluated. Compared with the low stability pure Bi anode, In–Sn–Bi alloy anodes show high reversible specific capacity and high cycle stability. Among the studied alloys, In10Sn10Bi80 electrode shows high reversible specific capacity up to 260 mAh g−1, good rate performance and excellent cycle stability (capacity retention above 98% after 80 cycles). The synergistic effects coming from the multi-phase structure have been clarified. The multi-phase structure resists the volume change and structural collapse and then guarantee the good cycle stability compared with that of pure Bi. Additionally, benefited by the fast kinetics of magnesiation/de-magnesiation of the dispersed Bi-rich phase, the reversibility of magnesiation/de-magnesiation of In and Sn are also realized. The multi-phase & fine-substructure design of the electrode materials is promising for the application in RMBs.