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

Abstract

We 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. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim