Amorphous Sn–Ni islets with high structural integrity as an anode material for lithium-ion storage

To the best of our knowledge, the study described herein is the first to demonstrate the use of amorphous Sn–Ni islets as an anode material for lithium-ion storage. The islets are prepared by co-electrodeposition (2 s). In general, amorphous Sn–metal alloys exhibit significantly improved cycling performances over those of crystalline alloys with similar compositions and morphologies. However, to date, no thermodynamically metastable amorphous phase has been found in Sn–Ni alloys of any composition. Here, we show that the amorphization of such alloys is possible by ensuring rapid co-electrodeposition, so as to prevent Sn and Ni from crystallizing. The resulting amorphous Sn–Ni alloy affords suppressed capacity degradation due to the preservation of its initial microislet-shaped particles and its structural integrity after cycling. This is primarily due to the volume changes in the amorphous phase being small. These findings indicate the potential of this newly developed amorphous Sn–Ni alloy to be used as an anode material for lithium-ion rechargeable batteries.