Co-doped Li4Ti5O12 nanosheets with enhanced rate performance for lithium-ion batteries

Co2+-doped Li4Ti5O12 (LTO) in the form of Li4Ti5-xCoxO12 (x = 0, 0.10, 0.15, 0.20) is prepared using a facile hydrothermal method. The doping of Co2+ leads to a decrease of the charge transfer resistance and improvement of the lithium ion diffusion coefficient. The as-prepared samples, Li4Ti5-xCoxO12 (x = 0.15) exhibits the best cycling stability and rate capability as anode material for lithium ion batteries, which delivers the initial specific capacity of 168.3,163,159,156.4,145.9,140.4,130.9 and 112.6 mAh g(-1) at 1, 2, 5, 10, 15, 20, 30 and 50C (1C = 175 mAh g(-1)) rate in the voltage range of 1.0-2.5 V respectively, and a discharge capacity of 109.3 mAh g(-1) after 1000 cycles at 50C. In addition, it keeps a discharge capacity of 150.8 mAh g(-1) (95.1% retention) at 5C even after 3000 cycles. Therefore, Co2+ doping technique provides an effective approach to improve electrochemical performances of LTO. (C) 2017 Elsevier Ltd. All rights reserved.