Dual phase Li4Ti5O12-TiO2 nanowire arrays as integrated anodes for high-rate lithium-ion batteries
Dual phase Li4Ti5O12-TiO2 nanowire arrays as integrated anodes for high-rate lithium-ion batteries
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DOI：
10.1016/j.nanoen.2014.06.032
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发表时间：
2014-10-01
期刊：
影响因子：
17.6
通讯作者：
Chen, Zhongwei
中科院分区：
文献类型：
--
作者：
Liao, Jin-Yun;Chabot, Victor;Chen, Zhongwei
钛酸锂（Li4Ti5O12）本身就是众所周知的零应变材料，作为锂离子电池负极，它具有出色的长循环稳定性。然而，低比容量（175 mA h g(-1)）限制了其在动力电池中的应用，尽管低电导率是另一个需要解决的固有问题。在这项工作中，我们开发了一种简便的水热和离子交换路线来合成自支撑双相Li4Ti5O12-TiO2纳米线阵列，以进一步提高其容量和倍率性能。双相Li4Ti5O12-TiO2纳米线中Li4Ti5O12与TiO2的比例约为2:1。 Li4Ti5O12中引入TiO2提高了比容量。更重要的是，通过界面设计，它创建了具有高晶界密度的双相纳米结构，有利于电子和锂离子的传输。与纯相纳米线Li4Ti5O12和TiO2纳米线阵列相比，双相纳米线电极具有优异的倍率性能（5 C时为135.5，10 C时为129.4，20 C时为120.2，30 C时为115.5 mAh g(-1)）。原位透射电子显微镜清楚地显示双相结构的变形接近于零，这解释了其优异的循环稳定性。 (C) 2014 Elsevier Ltd. 保留所有权利。
Lithium titanate (Li4Ti5O12) is well known as a zero strain material inherently, which provides excellent long cycle stability as a negative electrode for lithium ion batteries. However, the low specific capacity (175 mA h g(-1)) limits it to power batteries although the low electrical conductivity is another intrinsic issue need to be solved. In this work, we developed a facile hydrothermal and ionexchange route to synthesize the self-supported dual-phase Li4Ti5O12-TiO2 nanowire arrays to further improve its capacity as well as rate capability. The ratio of Li4Ti5O12 to TiO2 in the dual phase Li4Ti5O12-TiO2 nanowire is around 2:1. The introduction of TiO2 into Li4Ti5O12 increases the specific capacity. More importantly, by interface design, it creates a dual-phase nanostructure with high grain boundary density that facilitates both electron and Li ion transport. Compared with phase-pure nanowire Li4Ti5O12 and TiO2 nanaowire arrays, the dual-phase nanowire electrode yielded superior rate capability (135.5 at 5 C, 129.4 at 10 C, 120.2 at 20 C and 115.5 mA h g(-1) at 30 C). In-situ transmission electron microscope clearly shows the near zero deformation of the dual phase structure, which explains its excellent cycle stability. (C) 2014 Elsevier Ltd. All rights reserved.