Facile synthesis of low cost anatase titania nanotubes and its electrochemical performance

This work demonstrates a simple, large scale, cost effective facile route to a well crystallized only anatase TiO2 nanotube synthesized in Schlenk flask at 120 °C for 12 h in the 8 M KOH solution (TNTK) without a Teflon line autoclaves. For the first time all the XRD peaks at 2θ degrees of 25.39, 39.92, 48.11, 54.04, 55.03, 62.73, 68.97, 70.46, 75.48 corresponding to (101), (004), (200), (105), (211), (204), (116), (220), and (215) appeared in the final products contrary to the hydrothermal method where one/two anatase phases, often accompanied by a 2θ peaks at 14.5°. The as prepared nanotubes shows an outer diameter of ∼10 nm and inner diameter of ∼4.4 nm with a micrometers of tube lengths. It possess a high BET surface area of 203.75 m2/g with band gap of 3.70 eV, whereas 8 M NaOH solution (TNSNa) at the same condition gives a scattered flowered structure with tapering petals of surface area 71.5 m2/g and a mixed crystal phase of anatase/rutile and sodium hexatitanate. When these nanotubes applied as anode materials in LIBs, it shows an excellent first discharge/charge capacity of 635/240 mAhg−1 and retains 164 mAhg−1 after 36 cycles much higher than that of titanium dioxide nanoparticles and scattered flowers. The excellent performance can be ascribed to the 1D morphology, enhanced conductivity, fewer localized states near the band edges, high surface area and robustness of tubules which could effectively withstand expansion/contraction occurring during the lithium ion insertion/extraction process. Details of the synthesized nanotubes and electrochemical properties were characterized by HR-TEM, TEM-EDS, FE-SEM, XRD, XPS, UV-vis, electrochemical, CV, impedance and BET surface area techniques.