树枝状碳芯结构LiFePO_4/C复合材料的制备及电化学性能  

Preparation and electrochemical properties of branched LiFePO_4/C composite with carbon core structure

作　　者：陈晗[1] 龚文强[1] 刘友良[1] 刘建华[1] 

机构地区：[1]湖南工业大学冶金工程学院,株洲412000

出　　处：《中国有色金属学报》2010年第11期2206-2212,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50672024);湖南省自然科学基金资助项目(09JJ5010);湖南省教育厅青年基金资助项目(09B024)

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%。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.

关 键 词：LIFEPO4 复合材料 碳芯结构 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动]