制備及電化學性能
(湖南工業(yè)大學 冶金工程學院，株洲 412000)
摘 要: 采用環(huán)氧樹脂為碳源制備樹枝狀碳芯結構LiFePO4/C復合材料。利用X射線衍射、透射電鏡和X射線光電子能譜對復合材料進行分析，采用恒電流充放電和電化學阻抗方法研究試樣的倍率性能、循環(huán)性能和電化學阻抗。結果表明：樹枝狀LiFePO4/C復合材料的樹干是碳芯結構，由無定形碳芯和包覆在碳芯上的納米LiFePO4顆粒組成；樹枝狀碳芯結構LiFePO4/C復合材料在15 mA/g的電流密度下，首次放電容量達到167.4 mA·h/g；當電流密度增大到900 mA/g時，放電容量高達120.8 mA·h/g，經(jīng)過50次循環(huán)后，容量保持率高達99.5%。
關鍵字: LiFePO4；復合材料；碳芯結構；電化學性能
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
