Nanostructured materials based on Nb-doped titanium dioxide

Abstract

Oxide materials based on TiO2 (anatase) and doped with Nb5+ cations have been fabricated by the template sol-gel method. Two types of templates were used: activated carbon fiber and siloxane-acrylate emulsion. The morphology and structure of the samples have been studied and the conditions of their surface have been characterized. It has been demonstrated that the material morphology and structure are primarily determined by the type of the used template. Formation of microtubes consisting of nanoparticles (NP) on the carbon template was established. It has been shown that at the Nb-dopant content of up to 5 % (wt.) nanoparticles have the structure of anatase, in which the dopant cation occupies the position of the Ti4+ cation. Studies of the sample doped with 5 % Nb by the method of electrochemical impedance spectroscopy (EIS) demonstrated that introduction of Nb5+ ions into the TiO2 structure resulted in the increase of the material electroconductivity from 7.6⋅10-13 S/cm (nondoped sample) up to 2.3⋅10-7 S/cm. The increase of electroconductivity extends the potential fields of application of the above samples as anode materials for high-power Li-ion batteries. At using the siloxane-acrylate emulsion as a template, highly dispersed powders with a mesoporous structure consisting of heterogeneous in composition nanoparticles with a "core-shell" structure are formed.