Facile hydrothermal synthesis of porousTiO2 nanowire electrodes with high-rate capability for Li ion batteries

Abstract

Anatase TiO2 nanowires were successfully synthesized using a low-temperature hydrothermaltreatment on as-prepared one-dimensional (1D) hydrogen titanate nanowires (H2Ti3O7) at180 °C. Theanatase TiO2 nanowires were porous in nature with a high specific surface area. These nanowires werecharacterized using transmission electron microscopy (TEM), high-resolution TEM, x-raypowder diffraction, Raman spectroscopy, and Brunauer–Emmett–Teller (BET)measurements. The topochemical phase transformation mechanism fromH2Ti3O7 to anataseTiO2 is discussed. Theporous anatase TiO2 nanowire electrodes demonstrated an excellent cyclingperformance and superior rate capabilities compared with theH2Ti3O7 nanowires andthe anatase TiO2 nanowires that were prepared through calcination at700 °C. The porous anataseTiO2 nanowires exhibiteda capacity of ∼ 145 mA h g − 1 at 1 Cafter 500 cycles and 115 mA h g − 1 at 20 C. This improvement in the long-term cycle stability and outstanding ratecapability was explained by various microscopic observations of the porous 1Dnanostructured nature of the nanowires during the Li intercalation/deintercalation cycles.