Rational design of TiO2@ nitrogen-doped carbon coaxial nanotubes as anode for advanced lithium ion batteries

Abstract

To improve the lithium storage capacity, electrochemical kinetics and stability of TiO2 nanostructured electrode, a hybrid electrode of TiO2 nanotubes coated with nitrogen-doped carbon (TiO2@NC) was rationally designed and prepared. With the unique coaxial nanotube structure, the porous TiO2 nanotubes would offer short paths for Li+ diffusion and numerous active sites, while the N-doped carbon matrix would prefer fast charge transportation and buffer the volume change of TiO2 during lithiation/delithiation processes. In particular, a high reversible specific capacity of 480 mA h g−1 at a current density of 100 mA g−1 was achieved when evaluated as anodes for lithium ion batteries. The high capacity, outstanding cycling stability, and remarkable rate performance may attributed to its unique morphology and the synergetic effect of porous TiO2 nanotube and conductive N-doped carbon nanoshell on the basis of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).