Facile synthesis of surface fluorinated-Li4Ti5O12/carbon nanotube nanocomposites for a high-rate capability anode of lithium-ion batteries.

[Display omitted] • Uniform LTO/CNT nanocomposite was easily obtained via mechanofusion. • The surface of LTO/CNT was fluorinated via a simple post-treatment with NH 4 F. • The degree of fluorination was easily controlled by adjusting the amount of NH 4 F. • The fluorinated-LTO/CNT nanocomposites showed excellent electrochemical performance. Lithium titanate (Li 4 Ti 5 O 12 , LTO) with a spinel structure has attracted considerable attention as a promising anode material for application in lithium-ion batteries (LIBs) with high stability and long cycle life. However, the rate characteristics of the battery deteriorate due to its low electronic conductivity. In this study, a uniform nanocomposite was easily obtained by complexing bulk LTO particles and carbon nanotubes (CNTs) via mechanofusion. Additionally, without using hazardous reagents, the surface of the LTO/CNT nanocomposites could be easily fluorinated via a simple post-treatment using ammonium fluoride (NH 4 F). It was demonstrated that the degree of fluorination of the LTO/CNT nanocomposites could be easily controlled by adjusting the amount of NH 4 F. The surface fluorinated-LTO/CNT nanocomposites, in which the main strategies for improving electrical conductivity were introduced simultaneously, showed excellent electrochemical performance as anodes for LIBs. In particular, the optimized surface fluorinated-LTO/CNT nanocomposites not only exhibited a high specific capacity of 170.2 mAh g−1 at 0.2 C, but also maintained a capacity of ∼140 mAh g−1 at a high rate of 20 C, which was almost 2.3 times higher than that of bulk LTO particles. [ABSTRACT FROM AUTHOR]