双层碳包覆Li4Ti5O12的合成和电化学性能研究

采用固相合成方法制备了双层碳包覆Li_4Ti_5O_(12)复合材料.通过X射线衍射、扫描电子显微镜、循环伏安、电化学阻抗和恒流充放电分析等测试,研究了产物的结构、形貌及电化学性能.结果表明:通过碳包覆改性后,Li_4Ti_5O_(12)的容量可明显提高,碳的包覆对Li_4Ti_5O_(12)的结构没有影响;2 C倍率下首次放电比容量为118.8 mAh/g,300次循环后放电比容量仍为108.5 mAh/g,容量保持率为91.3%,具有非常好的电化学性能.

Synthesis and Electrochemical Properties of Double Carbon Coated Li4Ti5O12

Double layer carbon coated Li4Ti5O12 materials are prepared in a solid-state method. The structure, surface morphology and electrochemical properties of the products are characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge. It is found that carbon coating significantly improves the capacity of Li4Ti5O12. Carbon layer distributes on the surface of Li4Ti5O12 without destroying the crystal structure of the bulk material. The obtained Li4Ti5O12/C composite delivers a high initial discharge capacity of 118.8mAh/g at 2C rate and the capacity retention is 91.3% after 300 cycles, indicating superior electrochemical performance.