Facile synthesis of C–Fe3O4–C core–shell nanotubes by a self-templating route and the application as a high-performance anode for Li-ion batteries

In this study, we synthesized C–Fe3O4–C core–shell nanotubes through a facile chemical vapor deposition (CVD) method using Fe2O3 nanotubes as the self-templates. The hydrothermal product α-Fe2O3 hematite exhibits a tubular structure with an inner diameter of 70–100 nm, a wall thickness of 10–20 nm, and a length of 300–800 nm. After the CVD reaction in C2H2, α-Fe2O3 could be transformed into C–Fe3O4–C with the tubular structure reserved. The tubular C–Fe3O4–C is constructed by an Fe3O4 nanotube core and 5 nm thick carbon shells on both inner and outer surfaces of the Fe3O4 nanotube. The C–Fe3O4–C nanotube anode exhibits a stable cycling with a capacity over 700 mA h g−1 retained after 120 cycles at 100 mA g−1. The improved electrochemical properties of C–Fe3O4–C nanotubes compared with bare α-Fe2O3 could be attributed to the introduction of the carbon shells, which not only supplya high conductive channel and buffer matrix, but also keep the structural stability of the Fe3O4 nanotube upon cycling.