Carbon coated porous iron oxide nanotubes for optimized lithium storage

Iron oxide is intensively explored for its high capacity and abundant reserves. Suffering from poor conductivity and huge volume variation during repeating lithiation/delithiation, the capacity decays quickly. Herein, carbon coated porous iron oxide nanotubes (FeOx@C) is synthesized via hydrothermal method and subsequent annealing to achieve cycling stability. FeOx@C-2 exhibits excellent rate capability and superior cycling life. As anode material for lithium ion batteries, it delivers a high reversible capacity of 948.5 mAh g−1 at 2 A g−1 after 500 cycles. The initial coulombic efficiency is 88.7% and nearly 100% in the following cycles. The superior electrochemical performance belongs to improved electrical conductivity of carbon coating layer and exceptional stress relaxation of porous hollow structure of nanotube. •Amorphous carbon coated Fe3O4 porous nanotubes (FeOx@C) was synthesized.•The hollow structure of FeOx@C facilitates the Li+ diffusion and the structure integrity.•The carbon layer boosts the conductivity and accommodates the volume variation.•FeOx@C-2 exhibits superior lithium storage performance.