制备及电化学性能
(湖南工业大学 冶金工程学院，株洲 412000)
摘 要: 采用环氧树脂为碳源制备树枝状碳芯结构LiFePO4/C复合材料。利用X射线衍射、透射电镜和X射线光电子能谱对复合材料进行分析，采用恒电流充放电和电化学阻抗方法研究试样的倍率性能、循环性能和电化学阻抗。结果表明：树枝状LiFePO4/C复合材料的树干是碳芯结构，由无定形碳芯和包覆在碳芯上的纳米LiFePO4颗粒组成；树枝状碳芯结构LiFePO4/C复合材料在15 mA/g的电流密度下，首次放电容量达到167.4 mA·h/g；当电流密度增大到900 mA/g时，放电容量高达120.8 mA·h/g，经过50次循环后，容量保持率高达99.5%。
关键字: LiFePO4；复合材料；碳芯结构；电化学性能
branched LiFePO4/C composite with carbon core structure
（College of Metallurgy Engineering, Hunan University of Technology, Zhuzhou 412000, China）
Abstract:Branched LiFePO4/C composites with carbon core structure were synthesized with epoxy resin as carbon source. LiFePO4/C composites were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), and their electrochemical properties were investigated in terms of galvanostatic charge and discharge experiments and electrochemical impedance spectroscopy (EIS) tests. The results show that the branched LiFePO4/C composites possess carbon core structure which is composed of amorphous carbon core and nano-LiFePO4 grains. The initial discharge capacity of branched LiFePO4/C composite reaches 167.4 mA·h/g when current density of 15 mA/g is applied; when current density of 900 mA/g is applied, its discharge capacity is 120.8 mA·h/g and its capacity retention is 99.5% after 50 cycles.
Key words: LiFePO4; composite; carbon core structure; electrochemical property
