摘要
通过低温溶剂热法和高温热处理技术合成了橄榄石结构的LiFePO4/carbon(C-LiFePO4)纳米材料.在此基础上,通过溶液共混法制备了一种新型的聚三苯胺(PTPAn)修饰包覆的C-LiFePO4复合锂离子电池正极材料(C-LiFePO4/PTPAn).利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、电化学阻抗谱(EIS)以及恒电流充放电等测试方法,考察PTPAn包覆量对C-LiFePO4/PTPAn复合正极材料性能的影响.结果表明:通过溶液共混法PTPAn能够致密地包覆在C-LiFePO4表面,形成一个有效的电子/离子传输通道从而有效提高CLiFePO4基复合材料的电化学活性.所有样品中C-LiFePO4/10%(w)PTPAn作为正极材料呈现出最佳的电化学性能,在0.1C倍率恒流充放电下材料首次放电比容量为154.5 mAh g-1,在10C高倍率恒流充放电下材料的放电比容量达到114.2 mAh g-1.当C-LiFePO4/PTPAn复合材料表面包覆的PTPAn含量进一步增加,复合材料的电化学性能出现下降的趋势.电化学阻抗测试表明PTPAn包覆层明显减小了C-LiFePO4电极的电荷转移电阻.
An olivine LiFePOJcarbon （C-LiFePO,） nanocrystalline material was prepared using a low-temperature solvothermal method, followed by a high-temperature post-annealing process. Then polytriphenylamine （PTPAn）- modified C-LiFePO4 （C-LiFePOJPTPAn） was prepared, as a composite for novel cathodes for lithium-ion batteries, by solution blending of the C.-LiFePO4 nanocrystalline material and the electroactive conducting polymer PTPAn. The effects of PTPAn coating of the C,-LiFePOJPTPAn samples were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, electrochemical impedance spectroscopy （EIS）, and galvanostatic charge-discharge testing. The results indicated that the solution blending method produced a compact PTPAn coating on the C-LiFePO,, providing an effective electronic/ionic conducting pathway and enhancing the electrochemical activities of C-LiFePO4-based composites. The C-LiFePOJ10% （w） PTPAn electrode displayed an improved initial discharge capacity of 154.5 mAh. g-I at 0.1C, a superior high-rate performance discharge capacity of 114.2 mAh.g^-1 at 10C, and excellent cycling stability. With further increases in the PTPAn content of the coating on the C-LiFePO4/PTPAn composite, the electrochemical properties of the composite decreased. Electrochemical impedance measurements also demonstrated that the PTPAn coating significantly decreased the charge-transfer resistance of the C-LiFePO4 electrode.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2014年第1期88-94,共7页
Acta Physico-Chimica Sinica
基金
The project was supported by the National Natural Science Foundation of China(51003095,51103132)
Research on Public Welfare Technology Application Projects of Zhejiang Province,China(2010C31121)~~
关键词
锂离子电池
聚三苯胺
正极材料
溶液共混法
电化学性能
Lithium-ion battery
Polytriphenylamine
Cathode material
Solution blending method
Electrochemical property
作者简介
Corresponding authors. ZHANG Cheng, Email： czhang@zjut.edu.cn; Tel： ＋86-13336053516.
XU Li-Huan, Email： xulihuanss@163.com; Tel： ＋86-571-88320253.
