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.