Improving electrochemical properties of Li4Ti5O12/TiO2 diphase anode materials via Co-Cl co-doping

The rapid development of highly durable electric vehicles has put forward higher requirements for lithium-ion batteries. Li4Ti5O12 (LTO) is widely studied owing to its long service life and safety. However, owing to their low electrical conductivity and diffusion, lithium ions have limited practical applications. In this study, Co-Cl co-doped LTO/TiO2 diphase (LTOT) nanosheets were prepared via the hydrothermal method. The synergistic effect of Co-Cl co-doping reduced the charge-transfer resistance of LTOT and increased the lithium-ion diffusion coefficient, thereby improving the dynamic behavior of the electrode material, which further enhances the rate capability and cycle performance of LTOT. The optimized LTOT:Co-Cl composite exhibited excellent cycle performance and rate capability (the ninth cycle reversible capacities were 253.8, 222.2, 200.1, 185.7, 169.9, 161.3, and 146.3 mAh·g−1 at the current density of 1, 2, 5, 10, 20, 30, and 50 C (1 C = 175 mA·g−1) rate, respectively). In addition, LTOT:Co-Cl maintained a capacity of 120 mAh·g−1 after 5000 cycles at 50 C with a retention rate of 83 %, indicating that the average decay rate per cycle is only 0.003 % during the long charge/discharge process. [Display omitted] •The synergistic effect of Co-Cl provides outstanding electrochemical performance.•LTOT:Co-Cl has a high reversible capacity after 100 cycles at 1 C.•The capacity retention of LTOT:Co-Cl is 83% after 5000 cycles at 50 C.