High rate cycling performance of lanthanum-modified Li4Ti5O12 anode materials for lithium-ion batteries

A micro-sized particle Li4Ti5-xLaxO12 (0 <= x <= 0.2) material has been synthesized by a simple solid-state method at air. The obtained Li4Ti5-xLaxO12 materials are Li3xLa2/3-xTiO3 (LLTO)-Li4Ti5O12 (LTO) solid solution, and well crystallized with a particle size in the range of 1-2 mu m. The electronic conductivity and lithium diffusion coefficient of La-modified LTO (Li4Ti4.95La0.05O12) are improved because LLTO exhibits a high ionic conductivity during Li+ extraction. Li4Ti4.95La0.05O12 material shows discharge capacities of more than 206 and 197 mAh g(-1) after 100 cycles at 1 C and 3 C charge-discharge rates, respectively. Especially, in rate performance, the Li4Ti5-xLaxO12 (x = 0.1, 0.2) samples maintain capacity of about 181 mAh g(-1), until 5 C rates after 200 cycles, while the pure LTO sample shows a severe capacity decline at corresponding rate. These results suggest that La modifying is an effective way to improve the chemical stability of the electrode in contact with the electrolyte and improve their cyclability and rate capability during long term cycling. Since high rate performance is an important factor that needs to be considered in fabricating power batteries in industry, the La-modified LTO moves closer to real and large-scale applications. (C) 2012 Elsevier B.V. All rights reserved.