Facile hydrothermal synthesis of porous TiO2 nanowire electrodes with high-rate capability for Li ion batteries

Anatase TiO2 nanowires were successfully synthesized using a low-temperature hydrothermal treatment on as-prepared one-dimensional (1D) hydrogen titanate nanowires (H2Ti3O7) at 180 degrees C. The anatase TiO2 nanowires were porous in nature with a high specific surface area. These nanowires were characterized using transmission electron microscopy (TEM), high-resolution TEM, x-ray powder diffraction, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) measurements. The topochemical phase transformation mechanism from H2Ti3O7 to anatase TiO2 is discussed. The porous anatase TiO2 nanowire electrodes demonstrated an excellent cycling performance and superior rate capabilities compared with the H2Ti3O7 nanowires and the anatase TiO2 nanowires that were prepared through calcination at 700 degrees C. The porous anatase TiO2 nanowires exhibited a capacity of similar to 145 mA h g(-1) at 1 C after 500 cycles and 115 mA h g(-1) at 20 C. This improvement in the long-term cycle stability and outstanding rate capability was explained by various microscopic observations of the porous 1D nanostructured nature of the nanowires during the Li intercalation/deintercalation cycles.