Flower-like TiO2 hollow microspheres with mixed-phases for high-pseudocapacitive lithium storage

Abstract

Titanium dioxide (TiO2) is a typical lithium-ion storage material with the advantages of stable structure, abundant source and easy preparation. To further improve the lithium-ion diffusion, we employ a sol-gel method with a silicon dioxide (SiO2) template to prepare flower-like TiO2 hollow microspheres (TiO2 HM) with a loose surface structure composed of nanosheets. The as-prepared TiO2 exhibits a large specific surface area (120.3 m2/g) and pore volume (0.13 cm3/g), which favors the penetration of electrolyte. Moreover, the TiO2(B)/anatase/amorphous mixed phases have multitudes active sites for rapid lithium-ion diffusion. As an anode for lithium-ion batteries (LIBs), TiO2 HM deliver a high first discharge specific capacity (721 mAh/g, 0.1 A/g), superior rate capacity (84 mAh/g, 2.0 A/g) and long life (121 mAh/g, 1000 cycles, 1.0 A/g). Electrochemical analysis proves that Li+ ions storage of TiO2 HM is mainly dependent on pseudocapacitance (87%, 2.0 A/g). Therefore, it is an effective way to regulate morphology, composition and pseudocapacitance property with the SiO2 template of TiO2 for promising LIB anodes.