One-step vapor-solid reaction growth of Sn@C core-shell nanowires as an anode material for Li-ion batteries

Sn@C core-shell nanowires (NWs) were synthesized by reacting SnO2 particles with a flowing mixture of C2H2 and Ar gases at elevated temperatures. The overall diameter of the core-shell nanostructure was 100-350 nm. The C shell thickness was 30-70 nm. The NW length was several micrometers. Inside the shell, a void space was found. The reaction is proposed to be via a vapor-solid reaction growth (VSRG) pathway. The NWs were investigated as a potential anode material for Li-ion batteries (LIBs). The half-cell constructed from the as-fabricated electrode and a Li foil exhibited a reversible capacity of 525 mA h g(-1) after one hundred cycles at a current density of 100 mA g(-1). At a current density as high as 1000 mA g(-1), the battery still maintained a capacity of 486 mA h g(-1). The excellent performance is attributed to the unique 1D core-shell morphology. The core-shell structure and the void space inside the shell can accommodate large volume changes caused by the formation and decomposition of LixSn alloys in the charge-discharge steps.