Li_(0.99)Y_(0.01)FePO_4/C材料的合成与电化学性能

Synthesis and electrochemical performance of Li_(0.99)Y_(0.01)FePO_4/C composite materials

以酚醛树脂为碳源,利用固相反应合成了Li0.99Y0.01FePO4/C复合材料。采用X射线衍射分析(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)以及恒电流充放电等方法对该材料的晶体结构、表面形貌、界面结构及电化学性能进行表征。结果表明,所合成的Li0.99Y0.01FePO4/C材料为单一的橄榄石晶体结构,包覆碳后的复合材料颗粒形成了良好的导电网络,电化学性能得到很大改善。在0.1C的电流密度下进行充放电时,首次放电容量为143.43mAh/g,充放电效率为90.54%,在1.0C的电流密度下进行充放电时的首次放电容量仍有101.17mAh/g。

Li0.99Y0.01FePO4/C composite material was synthesized by solid state method with phenolic resin as carbon source.The crystalline structure,morphology of particles,structure of surface and electrochemical performance were characterized by X-ray diffraction,scanning electron microscopy,high resolution transmission electron microscope and galvanostatic experiments.The results show that the Li0.99Y0.01FePO4/C material is pure olive-type phase,the composite particles after covering with carbon constitute a well conductive network,therefore its electrochemical performance is greatly improved.When the current density is 0.1C,the fist discharge capacity is 143.43mAh/g and the charge-discharge efficiency is 90.54%,when the current density is 1.0C,the first discharge capacity is 101.17mAh/g.