Self-assembled synthesis of monodispersed mesoporous Li4Ti5O12 beads and their applications in secondary lithium-ion batteries

Monodispersed mesoporous lithium titanate was synthesized by combining sol-gel and solvothermal process. The role of solvothermally treating amorphous TiO2 precursors could produce mesoporous anatase beads with the incorporation of Li2O. Calcination helps the diffusion between TiO2 and Li2O, leading to mesoporous lithium titanate. The crystalline structure and morphological observation of the as-synthesized mesoporous Li4Ti5O12 were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The mesoporous structure could be directly observed through the N-2 adsorption/desorption isotherm. It was demonstrated that the electrochemical performance was significantly improved by the mesoporous structure. The mesoporous lithium titanate exhibited a stable capacity of 160 mAh g(-1) at 0.5 C. Besides, the reversible capacity at 5 C remained over half of that at 0.5 C. The superior C-rate performance should be associated with the mesoporous structure, facilitating lithium transportation ability during cycling. (C) 2012 Elsevier Ltd. All rights reserved.