Mixed-Surfactant-Assisted Synthesis of Dual-Phase Li4 Ti5 O12 -TiO2 Hierarchical Microspheres as High-Performance Anode Materials for Li-Ion Batteries.

Abstract

A mixed-surfactant-assisted method was developed to synthesize dual-phase Li4 Ti5 O12 -TiO2 hierarchical microspheres. The ratio of anionic/cationic surfactant could regulate the primary structure morphology and the dual-phase ratio of the final product, in which the primary structure morphology could be stacked nanosheets, small nanoparticles, or large nanoparticles. The sample with a primary structure morphology of small nanoparticles had the highest specific surface area of 79.38 m2 g-1 and the best electrochemical performance because of its high Li+ migration rate, low polarization, and appropriate TiO2 content. Its capacity reached 153.5 mA h g-1 at a current rate of 40 C, and it retained nearly 100 % of its capacity after 100 cycles. A self-assembly mechanism of the mixed surfactant was highlighted to explain the formation of hierarchical microspheres. The physical and electrochemical properties of obtained material were correlated effectively.