High capacity TiO2 anode materials for Li-ion batteries

• Carbon nanotube based buckypapers were produced from multiwall carbon nanotubes via vacuum filtration method.
• TiO2 thin films were deposited by magnetron sputtering on buckypapers followed by in situ DC plasma oxidation.
• Increasing oxygen content decreased the mean grain size and increased the total battery capacity and ohmic resistance.

Carbon nanotube thin sheets – buckypapers – were prepared from multi-walled carbon nanotubes oxidized with different oxidation agents. Titanium dioxide films were then deposited by magnetron sputtering of Ti films on buckypapers substrates followed by in situ DC plasma oxidation. The effect of oxygen partial pressure on the structural, compositional and electrochemical properties of the films was investigated. The mean grain sizes of the deposited films were found to be in the range of 2.27–7.39 nm as revealed by the SEM and XRD studies. The electrochemical studies were performed with pure metallic Li foil cathode with the best performing nanostructured-TiO2 as anode. Cyclic voltammetry and impedance tests were also performed in order to evaluate the battery capacity.