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

- Li4Ti5O12 and Co2+-doped Li4Ti5O12 nanosheets are prepared and investigated in LIBs.
- A capacity of 112.6 mAh g−1 for the Li4Ti4.85Co0.15O12 electrode is obtained in LIBs at 50C.
- A capacity of 150.8 mAh g−1 (95.1% retention) for the Li4Ti4.85Co0.15O12 electrode is obtained in LIBs at 5C after 3000 cycles.

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.