改性钛酸锂复合材料作为高倍率锂离子电池负极材料研究

Preparation of Li_4Ti_5O_(12)/C Composite and Its Application to Anode Material of High Rate Lithium-ion Battery

使用简单的水解反应和低温热处理过程所制备的Li_4Ti_5O_(12)/C复合材料具有良好的倍率性能。在水解过程中引入表面活性剂溴化十六烷基三甲铵(CTAB),能够明显地改善锂离子电池负极材料Li_4Ti_5O_(12)/C的倍率性能。在0.5,1,2,5,10C的倍率条件下,电极材料的比容量分别达到162,154,121,80,60 m Ah/g。明显高于使用物理混合方法所制备的Li_4Ti_5O_(12)/C复合材料。同时使用CTAB所制备的Li_4Ti_5O_(12)/C复合材料,在高倍率条件下,还显示出了非常良好的循环稳定性,因为其拥有快速的Li+迁移速率(8.97×10-13cm2/s),较小的传荷电阻(Rct)35.2Ω和较小的体积电阻(Rs)6.8Ω。该方法具有实际的应用价值。

The Li_4Ti_5O_(12)/C( LTO/C) composite with excellent rate performances was synthesized via a facile hydrolysis reaction followed by a low temperature heat treatment. In the hydrolysis process,the introduction of cetyltrimethylammonium bromide( CTAB) as a surfactant can significantly improve the rate performances of Li_4Ti_5O_(12)/C composite as anode material for lithium ion battery( LIB). The specific capacities of the obtained composite at charge and discharge rates of 0. 5,1,2,5 and 10 C were respectively162,154,121,80 and 60 m Ah/g,which was apparently larger than those of the Li_4Ti_5O_(12)/C by physical mixing processes. The Li_4Ti_5O_(12)/C prepared with CTAB also showed excellent cycling stability at high rate,attributed to its larger diffusion coefficient of lithium ion( 8. 97 × 10-13cm^2/s),smaller charge-transfer resistance Rct( 35. 2 Ω) and volume resistance Rs( 6. 8 Ω) than those of the composite by physical mixing. Therefore,this study has important theory significance and practical application value.