Fe 3 O 4 @C Nanotubes Grown on Carbon Fabric as a Free‐Standing Anode for High‐Performance Li‐Ion Batteries

Recently, Li‐ion batteries (LIBs) have attracted extensive attention owing to their wide applications in portable and flexible electronic devices. Such a huge market for LIBs has caused an ever‐increasing demand for excellent mechanical flexibility, outstanding cycling life, and electrodes with superior rate capability. Herein, an anode of self‐supported Fe 3 O 4 @C nanotubes grown on carbon fabric cloth (CFC) is designed rationally and fabricated through an in situ etching and deposition route combined with an annealing process. These carbon‐coated nanotube structured Fe 3 O 4 arrays with large surface area and enough void space can not only moderate the volume variation during repeated Li + insertion/extraction, but also facilitate Li + /electrons transportation and electrolyte penetration. This novel structure endows the Fe 3 O 4 @C nanotube arrays stable cycle performance (a large reversible capacity of 900 mA h g −1 up to 100 cycles at 0.5 A g −1 ) and outstanding rate capability (reversible capacities of 1030, 985, 908, and 755 mA h g −1 at 0.15, 0.3, 0.75, and 1.5 A g −1 , respectively). Fe 3 O 4 @C nanotube arrays still achieve a capacity of 665 mA h g −1 after 50 cycles at 0.1 A g −1 in Fe 3 O 4 @C//LiCoO 2 full cells.