Sphere-like SnO2/TiO2 composites as high-performance anodes for lithium ion batteries

Abstract

A novel sphere-like SnO2/TiO2 composite is synthesized via spray-drying followed by calcination as confirmed by X-ray diffraction and field emission-scanning electron microscopy analyses; the SnO2/TiO2 composite is composed of the tetragonal cassiterite-like SnO2 nanoparticles and anatase-like TiO2 nanospheres. The characterization results show that the optimal stoichiometric ratio of SnO2/TiO2 is approximately 3:1 when the composite serves as the anode for lithium ion batteries, in which the composite electrode not only delivers a high initial discharge specific capacity of 1476 mAh g−1 and retains 483 mAh g−1 after 40 cycles at 500 mA g−1 but also presents a low transfer resistance of approximately 56.33 Ω, a high Warburg coefficient of up to 85.82 Ω cm2 s−0.5, and a high lithium ion diffusion coefficient of approximately 6.934 E-15 cm2 s−1 at ambient temperature. These excellent electrochemical properties suggest that the SnO2/TiO2 composite electrode may be a promising anode material for lithium ion batteries.