Anatase/rutile TiO2 nanocomposite microspheres with hierarchically porous structures for high-performance lithium-ion batteries

Abstract

A new anatase/rutile TiO₂ nanocomposite microspheres (ART) electrode with hierarchically porous structures was successfully synthesized by a one-step route under mild hydrothermal conditions. The morphology, crystal structure and phase composition, specific surface area and pore size distribution of the obtained nanocomposite were systematically investigated by X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and nitrogen adsorption–desorption measurements. The as-synthesized nanocomposite microspheres electrodes exhibited superior specific capacity and high-rate charge–discharge performance for lithium-ion batteries (LIBs) (∼103 mA h g⁻¹ at 30 C after 100 charge–discharge cycles, 1 C = 170 mA g⁻¹) as compared to commercial TiO₂ nanoparticles (P25). The improvement is mainly attributed to enhanced Li-ion diffusion and efficient charge transport as evidenced from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. Most importantly, the materials architecture used in this study, comprising of dual-phase TiO₂ nanocrystals with hierarchically porous structures would be a general concept that could be applicable in the development of other mixed-phase electrode materials for rechargeable lithium-ion batteries and supercapacitors.