Effect of Sn-doping on the electrochemical behaviour of TiO2 nanotubes as potential negative electrode materials for 3D Li-ion micro batteries
Résumé
Self-organized Sn-doped TiO2 nanotubes were fabricated by anodization of co-sputtered Ti-Sn thin films in a glycerol electrolyte containing NH4F. The Sn-doped TiO2nts were studied in terms of composition, morphology and structure by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and 119Sn Mössbauer spectroscopy. The electrochemical behaviour of the Sn-doped TiO2nts was evaluated in Li test cells as a possible negative electrode for 3D Li-ion micro batteries. The Sn-doped TiO2nts delivered much higher capacity values compared to simple TiO2nts. The outstanding electrochemical behaviour is proposed to be related to the enhanced lithium diffusivity evidenced with Cottrell plots, and the rutile-type structure imparted with the Sn doping.