Superior cycle performance of Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries

A novel anode material for lithium-ion batteries, tin nanoparticles coated with carbon embedded in graphene (Sn@C/graphene), was fabricated by hydrothermal synthesis and subsequent annealing. The structure and morphology of the nanocomposite were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The size of the Sn@C nanoparticles is about 50–200 nm. The reversible specific capacity of the nanocomposite is ∼662 mAh g−1 at a specific current of 100 mA g−1 after 100 cycles, even ∼417 mAh g−1 at the high current of 1000 mA g−1. These results indicate that Sn@C/graphene possesses superior cycle performance and high rate capability. The enhanced electrochemical performances can be ascribed to the characteristic structure of the nanocomposite with both of the graphene and carbon shells, which buffer the volume change of the metallic tin and prevent the detachment and agglomeration of pulverized tin.