An Investigation on the Effect of Li–Ion Cycling on the Vertically Aligned Brookite TiO2 Nanostructure

Abstract

AbstractWe reported the investigation on the effect of Li‐ion cycling on the vertically aligned brookite (β) TiO2 nanorods coated on Cu substrate as a Li‐ion battery electrode. The vertically grown β‐TiO2 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‐TiO2 nanorods and Raman spectroscopy revealed the formation of pure brookite phase, and not accompanied by the anatase and/or rutile phases. The β‐TiO2 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‐TiO2 nanorods with a high coulombic efficiency of greater than ∼98% confirms their potentials as a competent electrode for Li‐ion rechargeable batteries.