Ultrathin N-doped carbon-coated TiO2 coaxial nanofibers as anodes for lithium ion batteries.

The structural optimization of TiO₂ materials has a significance for improving the electrochemical performance since TiO₂ suffers from poor electronic conductivity. For this purpose, ultrathin N-doped carbon-coated TiO₂ coaxial nanofibers have been designed and synthesized by a facile electrospinning approach. Microstructure analysis indicates that the TiO₂ nanofibers can be coated by the ultrathin carbon layers. Electrochemical tests reveal that the rate performance and cycling ability of TiO₂@C nanofibers have been enhanced obviously. The TiO₂@C6 nanofibers carbonized at 600°C exhibit superior features with a specific discharge capacity of 284 mAh g⁻¹ at a current density of 100 mA g⁻¹ after 100 cycles. Besides improved rate performance of 117 mAh g⁻¹ at a high current density of 2000 mA g⁻¹ and excellent cycling stability with only about 0.008% capacity loss per cycle were also obtained in the sample TiO₂@C6 after 500 cycles at the current density of 1000 mA g⁻¹. Such remarkable performance may be ascribed to the unique one-dimensional nanofibers as flexible carbon matrix. [ABSTRACT FROM AUTHOR]