Controlled carbon coating of Fe 2 O 3 nanotube with tannic acid: A bio-inspired approach toward high performance lithium-ion battery anode

Transition metal oxides are promising anode materials for lithium ion battery (LIB). However, it suffers from the great volume changes during the charge-discharge cycles of the battery. A bio-inspired coating approach is developed to synthesize carbon coated Fe2O3 nanotube. This novel approach involves the use of tannic acid as the coating agent and enables formation of stable coating on Fe2O3 nanotube instantaneously. The initial discharge capacity of the carbon coated Fe2O3 is as high as 1452.9 mAh g−1 at 0.2 C. In addition, the discharge capacity of the carbon coated Fe2O3 reaches 551.3 mAh g−1 after 200 cycles at 0.2 C, significantly higher than that for the pristine Fe2O3 (201.7 mAh g−1). The good rate performance of the carbon coated Fe2O3 is also proved. These results not only suggest that the carbon coated Fe2O3 is highly promising for practical LIB applications but also indicate the tannic acid mediated carbon coating method can serve as an effective and universal approach for the functionalization of electrode materials.