Porous nanocrystalline TiO₂ with high lithium-ion insertion performance

Porous nanocrystalline anatase TiO₂ was prepared by a modified hydrolytic route coupled with an intermediary amorphization/recrystallization process. The phase structure and morphology of the products were analyzed by X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. The electrochemical properties were investigated by cyclic voltammetry, constant current discharge-charge tests, and electrochemical impedance techniques. Applied as an anode in a lithium-ion battery, the material exhibited excellent specific capacities of 130 mAh g^-1 (at the rate of 2000 mA g^-1) and 96 mAh g^-1 (at the rate of 4000 mA g^-1) after 100 cycles; the coulombic efficiency was ~99.5 %, indicating excellent rate capability and reversibility. Furthermore, the electrochemical impedance spectra showed improved electrode kinetics after cycling. These results indicate that the porous nanocrystalline TiO₂ synthesized by this improved synthesis route might be a promising anode material for high energy and high power density lithium-ion battery applications.