Preparation and electrochemical lithium storage features of TiO2 hollow spheres.

Abstract: Uniform and monodispersed TiO2 hollow spheres with nanoporous titania shell are prepared successfully by using carboxyl-functionalized polystyrene spheres as templates. The results show that TiO2 hollow spheres pose a stable reversible capacity of 230 mAhg−1 at 33.5 mAg−1 and 120 mAhg−1 at 1675 mAg−1, which are higher than that of bulk TiO2 with coarse grain. The discharge process of TiO2 hollow spheres are suggested containing three consecutive stages: the formation of tetragonal Li x TiO2 solid solution, coexistence of two-phase mixture of Li0.05TiO2 and Li0.5TiO2 at 1.75 V and additional lithium storage in the surface. The superior high rate and high capacity performance of prepared TiO2 hollow spheres are due to its highly reversible additional surface capacities and accommodation of phase transformation within nanostructure. [Copyright &y& Elsevier]