Facile Synthesis of Donut-like TiO<sub>2</sub>-SnO<sub>2</sub> Nanocomposite Microspheres by a Two-step Hydrothermal Reaction and Subsequent Spray Drying Process and Its Electrochemical Lithium Storage Properties

Abstract

Donut-like TiO2-SnO2 nanocomposite microspheres were successfully synthesized via a facile two-step hydrothermal reaction and subsequent spray drying. The protonated titanate nanowires with H2Ti3O7 phase in the nanocomposite precursor transformed into not anatase TiO2 but TiO2(B) crystal structure even after calcination at 400 ?. And the substitutional solid solution (Sn, Ti)O2 with the same tetragonal rutile structure as SnO2 was formed. Moreover, the hierarchical donut-like structure in TiO2-SnO2 nanocomposite microspheres constructed by the second-step hydrothermal and spray drying treatment was maintained after calcination at 400 ?. The electrochemical test showed that the as-obtained TiO2-SnO2 nanocomposite microspheres reached an initial discharge capacity of 640 m Ah g-1 at a current density of 40 mA.g-1, which is much higher than the theoretical capacity of TiO2(B).