Hollow Core-Shell Mesoporous TiO2 Spheres for Lithium Ion Storage

Hollow core-shell mesoporous TiO2 spheres have been synthesized by a hydrothermal reaction without surfactant, followed by firing at 500 degrees C. X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), and Barrett-Joyner-Halenda (BJH) data reveal a mesoporous and nanosize building-block morphology with large surface area. The samples have an average pore size, surface area, and total pore volume of 8 nm, 131 m(2)/g, and 0.2 cm(3)/g, respectively. The hollow core-shell mesoporous TiO2 spheres exhibit a high capacity of >200 mAh/g with good cyclability and high rate capability as the mesoporous, nanosize building-block morphology of TiO2 spheres provides good electrical contact, accommodates the strain smoothly, and facilitates facile lithium-ion diffusion.