Hierarchical Li4Ti5O12-TiO2 microspheres assembled from nanoflakes with exposed Li4Ti5O12 (011) and anatase TiO2 (001) facets for high-performance lithium-ion batteries

摘要

Hierarchical Li4Ti5O12-TiO2 microspheres are synthesized via an oil/water interface method with the assistance of cetyltrimethylammonium bromide (CTAB) and following calcination. The as-prepared Li4Ti5O12-TiO2 microspheres are consisted of nanoflakes (ca. 15 nm in thickness); moreover, Li4Ti5O12 and anatase TiO2 in the nanoflake building blocks are bounded by (011) and (001) facets, respectively. More especially, it is found that CTAB plays a very important role in the phase and morphology of the Li4Ti5O12-TiO2 composite. When employed as the anode materials for lithium-ion batteries, the Li4Ti5O12-TiO2 microspheres show initial discharge capacities of 234, 170, 151 and 140 mAh g(-1) at charge/discharge rate of 1, 5, 10, and 20C, respectively; furthermore, after 100 cycles at 5C, the discharge capacity remains at 158 mAh g(-1) with a capacity retention of 92.9%. The excellent electrochemical properties of the product can be ascribed to the synergistic effect of the exposed Li4Ti5O12 (011) and anatase TiO2 (001) facets, abundant phase interfaces, hierarchical structures, and thin flake-like building blocks. (C) 2016 Elsevier Ltd. All rights reserved.