Monodisperse LiFePO4 microspheres embedded with well-dispersed nitrogen-doped carbon nanotubes as high-performance positive electrode material for lithium-ion batteries
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- 作者：Xiaofeng Tu ; Yingke Zhou ; zhouyk888@hotmail.com ; Xiaohui Tian ; Yijie Song ; Chengji Deng ; Hongxi Zhu
- 关键词：LiFePO4 microsphere ; nitrogen-doped carbon nanotube ; positive electrode ; lithium-ion battery
- 刊名：Electrochimica Acta
- 出版年：2016
- 出版时间：20 December 2016
- 年：2016
- 卷：222
- 期：Complete
- 页码：64-73
- 全文大小：4048 K
- 卷排序：222
文摘
Monodisperse LiFePO4 microspheres embedded with well dispersed nitrogen doped carbon nanotubes (N-CNTs) are synthesized by chemical lithiation of the pre-synthesized FePO4/N-CNTs precursor. The morphology and structure of the composite microspheres are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the LiFePO4 microsphere to construct a superior three-dimensional conductive network, which allows for efficient charge transfer, ensures short lithium-ion diffusion distance, and facilitates the ion and electron transport throughout the active materials. The LiFePO4/N-CNTs microsphere composites display a reversible discharge capacity of 153 mAh g−1 at 0.1C, a rate capability of 106 mAh g−1 at a high rate of 10C, and an excellent cycling stability (>97% capacity retention after 500 cycles), which are promising positive electrode materials for application in high-performance lithium-ion batteries.