Enhanced high rate capability of dual-phase Li4Ti5O12-TiO2 induced by pseudocapacitive effect
Enhanced high rate capability of dual-phase Li4Ti5O12-TiO2 induced by pseudocapacitive effect
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DOI：
10.1016/j.electacta.2011.07.101
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发表时间：
2011-10-30
影响因子：
6.6
通讯作者：
Gao, X. P.
中科院分区：
文献类型：
--
作者：
Li, X.;Lai, C.;Gao, X. P.
采用添加硫脲的水热法成功合成了双相Li 4 Ti 5 O 12-TiO 2纳米复合材料。采用恒电流法、循环伏安法和交流阻抗法研究了该双相纳米复合材料作为锂离子电池负极的电化学性能。结果表明，双相Li 4 Ti 5 O 12-TiO 2纳米复合材料的电化学性能优于单一相Li 4 Ti 5 O 12和TiO 2样品。在1C下循环300次后，双相Li 4 Ti 5 O 12-TiO 2纳米复合材料仍能保持116 mAh g（-1）的大容量放电。结果表明，所制备的纳米复合材料能够承受不同放电电流密度的较大变化，保持良好的稳定性。在1600 mA·g（-1）的大电流密度下循环，放电容量达到132 mAh·g（-1）。循环伏安测试结果表明，由于双相Li 4 Ti 5 O 12-TiO 2纳米复合材料中存在丰富的相界面，产生了赝电容效应，有利于提高材料的高倍率性能和良好的循环稳定性。(C)2011爱思唯尔有限公司版权所有。
The dual-phase Li4Ti5O12-TiO2 nanocomposite is successfully synthesized by a hydrothermal route with adding thiourea. The electrochemical performance of the dual-phase nanocomposite as anode for lithium-ion batteries is investigated by the galvanostatic method, cyclic voltammetry and electrochemical impedance spectra. It is demonstrated that the dual-phase Li4Ti5O12-TiO2 nanocomposite presents the improved electrochemical performance over individual single phase Li4Ti5O12 and anatase TiO2 samples. After 300 cycles at 1 C, the dual-phase Li4Ti5O12-TiO2 nanocomposite can still maintain the large discharge capacity of 116 mAh g(-1). It indicates that the as-prepared nanocomposite can endure great changes of various discharge current densities to retain a good stability. The large discharge capacity of 132 mAh g(-1) is also obtained at the large current density of 1600 mA g(-1) upon cycling. In particular, as verified by the cyclic voltammetry, the pseudocapacitive effect is induced due to the presence of abundant phase interfaces in the dual-phase Li4Ti5O12-TiO2 nanocomposite, which is beneficial to the enhanced high rate capability and good cycle stability. (C) 2011 Elsevier Ltd. All rights reserved.