Enhancing Lithium Storage Performances of the Li₄Ti₅O₁₂Anode by Introducing the CuV₂O₆Phase

The low electronic conductivity of spinel-structured Li4Ti5O12 could be improved by introducing CuV2O6. Herein, several Li4Ti5O12/CuV2O6 composites with different CuV2O6 contents have been successfully prepared by a facile liquid-phase dispersion technique. The amount of CuV2O6 in composites is shown to affect the particle size and electrochemical performances of Li4Ti5O12. The Li4Ti5O12/CuV2O6 composite prepared with a 5 wt % CuV2O6 content (referred to as 5 wt % Li4Ti5O12/CuV2O6) exhibits the best electrochemical performances among all the Li4Ti5O12/CuV2O6 composites. The initial discharge/charge capacities of the 5 wt % Li4Ti5O12/CuV2O6 composite reach 241.1/199.8 mAh g–1 and retain at 136.8/135.7 mAh g–1 over 500 cycles at 30 mA g–1 between 1.0 and 3.0 V. In addition, initial discharge/charge capacities of the 5 wt % Li4Ti5O12/CuV2O6 composite amount to 129.8/90.5 mAh g–1 even at 1200 mA g–1 with maintained discharge/charge capacities of 71.1/71.1 mAh g–1 over 2500 cycles, which are superior to the pristine Li4Ti5O12 in all cases. The detailed electrode kinetic analysis reveals that the introduction of the CuV2O6 phase can enhance the lithium-ion transferring rate and cycling stability of Li4Ti5O12. The enhanced lithium-storage mechanism of the 5 wt % Li4Ti5O12/CuV2O6 composite is clarified by in situ X-ray diffraction (XRD) analysis. The acquired data confirms that in situ formation of small amounts of metallic Cu during discharge/charge processes highly enhance the electronic conductivity and decreases the charge–transfer resistance of Li4Ti5O12. In sum, the as-obtained 5 wt % Li4Ti5O12/CuV2O6 composite has potential for future construction of high-rate and long-lifespan anode materials for Li-ion batteries. The work also provides an innovative route to improve electrochemical performances of Li4Ti5O12.