Effects of sodium content of titanate nanotubes on lithium battery performance

Titanate nanotubes were prepared by hydrothermal process of powder for the application to the anode of lithium batteries. After the synthesis of titanate nanotubes by the chemical treatment with 10 M NaOH solution, the quantity of sodium remnant was controlled by the HCl washing solutions of different pH of 1, 4, 7, 10 and 13. The prepared titanate nanotubes had outer and inner diameter of 9 nm and 6 nm, and the interlayer spacing of about 1 nm. The amount of sodium remnant was investigated using Inductively Coupled Plasma (ICP) Atomic Emission Spectrometer, and the variation of structure and morphology with the contents of the sodium was studied by X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FE-SEM) and High Resolution Transmission Electron Microscopy (HR-TEM). Coin cells composed of (Titanate nanotubes//1 M LiPF6-EC/DEC//Li metal) were prepared for studying the basic charging-discharging behavior and electrochemical properties of the prepared titanate nanotubes with controlled sodium contents. The effects of the remnant sodium content on the microstructures, morphology and electrochemical properties of titanate nanotubes will be discussed.