Lithium-ion battery anode properties of TiO2 nanotubes prepared by the hydrothermal synthesis of mixed (anatase and rutile) particles

From mixed (anatase and rutile) bulk particles, anatase TiO2 nanotubes are synthesized in this study by an alkaline hydrothermal reaction and a consequent annealing at 300–400 °C. The physical and electrochemical properties of the TiO2 nanotube are investigated for use as an anode active material for lithium-ion batteries. Upon the first discharge–charge sweep and simultaneous impedance measurements at local potentials, this study shows that interfacial resistance decreases significantly when passing lithium ions through a solid electrolyte interface layer at the lithium insertion/deinsertion plateaus of 1.75/2.0 V, corresponding to the redox potentials of anatase TiO2 nanotubes. For an anatase TiO2 nanotube containing minor TiO2(B) phase obtained after annealing at 300 °C, the high-rate capability can be strongly enhanced by an isotropic dispersion of TiO2 nanotubes to yield a discharge capacity higher than 150 mAh g−1, even upon 100 cycles of 10 C-rate discharge–charge operations. This is suitable for use as a high-power anode material for lithium-ion batteries.