电极活性材料Li4Ti5O12的制备及电化学性能

Preparation and electrochemical properties of Li4Ti5O12 as an electrode material

  • 摘要: 以LiNO3和TiO2为初始反应物,固相法合成了Li4Ti5O12(M1).X射线衍射实验结果表明,所得粉体为较纯的尖晶石结构的Li4Ti5O12复合氧化物.Li4Ti5O12电极以35mA·g-1电流密度恒流充放电,首次放电容量达到170mAh·g-1,接近理论容量,首次充放电效率为92%.其在大电流密度下充放电性能良好,以175,350,875mA·g-1的电流密度放电,放电容量分别达到了151,140,115mAh·g-1;与传统方法使用LiOH和TiO2固相合成的Li4Ti5O12(M2)加以比较,3个倍率下的放电容量分别提高了约5%,10%和26%.循环伏安曲线表明:M1电极电位极化小,可逆性好,电极电化学活性高;M1电极嵌入/脱出锂后交流阻抗测试表明其电化学反应阻抗分别为16和20Ω.

     

    Abstract: Li4Ti5O12(M1) was obtained by solid reaction process with LiNO3 and TiO2 as reactants. XRD analysis indicates that the main phase of the produced powder is Li4Ti5O12 compound oxide with spinel structure. The initial discharge capacity of M1 at 35 mA·g-1 reaches 170 mAh·g-1, which is comparable to the theoretical capacity, and the first coulombic efficiency is 92%. M1 performs well when it charges and discharges with high current density, and the discharge capacities reach 151, 140 and 115 mAh·g-1 at 175, 350 and 875 mA·g-1, respectively. The discharge capacities of M1, comparing with that of ME prepared by conventional solid-state sintering of LiOH and TiO2, increase by 5%, 10% and 26% at 175, 350 and 875 mA·g-1, respectively. Cyclic voltammogram suggests that the electrode of M1 has low polarization, good reversibility and high electrochemical activity. The charge transfer resistances of M1 measured through AC impedance are 16 and 2012 after lithium insertion and extraction, respectively.

     

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