An Investigation on the Effect of Li–Ion Cycling on the Vertically Aligned Brookite TiO 2 Nanostructure

We reported the investigation on the effect of Li‐ion cycling on the vertically aligned brookite (β) TiO 2 nanorods coated on Cu substrate as a Li‐ion battery electrode. The vertically grown β‐TiO 2 nanorods synthesized over large area array using hot filament metal vapor deposition (HFMVD) technique were ∼19 nm in diameter with well‐defined textural boundaries. X‐ray photoelectron spectroscopy revealed the formation of stoichiometric β‐TiO 2 nanorods and Raman spectroscopy revealed the formation of pure brookite phase, and not accompanied by the anatase and/or rutile phases. The β‐TiO 2 nanorods showed good electrochemical performance with the appearance of the potential plateau at 1.8 and 2.1 V during Li insertion and desertion. The initial discharge/charge capacities of ∼81 (52 μAh cm −2 μm −1 ) and ∼72 mAhg −1 (45 μAh cm −2 μm −1 ) obtained at the current density of 33 mAg −1 were retained further to ∼62 mAhg −1 (40 μAh cm −2 μm −1 ) until the 200th cycle. The exceptional cycling performance of β‐TiO 2 nanorods with a high coulombic efficiency of greater than ∼98% confirms their potentials as a competent electrode for Li‐ion rechargeable batteries.