Nanoscale size effect of titania (anatase) nanotubes with uniform wall thickness as high performance anode for lithium-ion secondary battery

We report the synthesis of titania (TiO2) nanotubes (NTs) with precisely controlled wall thickness by atomic layer deposition (ALD) using alumina membranes as template and their application as anode material for lithium (Li) ion storage in secondary battery. As-grown nanotubes are amorphous in nature and transform into anatase phase by subsequent thermal annealing. The charge/discharge capacities and rate performance are found to be dependent on the wall thickness, which is highly uniform, of the NTs. Maximum reversible capacity for Li-insertion in anatase TiO2 ∼ 330 mAh g−1 has been achieved by reducing the tube wall thickness to 5 nm. NTs with the wall thickness of 40 nm show reversible capacity of ∼170 mAh g−1 which is similar to the maximum theoretical capacity of the bulk anatase as reported. With decrease in the wall thickness, rate performance of the NTs is significantly improved. NTs with 5 nm in the wall thickness render excellent rate capability and cycle response.

Graphical abstractTiO2 nanotubes with precisely controlled wall thickness have been synthesized by atomic layer deposition and their application as anode material for Li-ion storage in secondary battery has been studied. The charge/discharge capacities and rate performance are dependent on the tube wall thickness. Nanotubes with 5 nm in the wall thickness render excellent specific capacity, rate capability and cyclability.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of TiO2 nanotubes with precisely controlled and uniform wall thickness by atomic layer deposition has been reported. ► The “true” nano-size effect in tubular structure for the hosting of Li-ions has been explored for first time by studying the electrochemical properties of TiO2 nanotubes for various wall thicknesses. ► The electrochemical performances are dependent on the tube wall thickness and the nanotubes with 5 nm wall thickness render excellent rate capability and cycle response.