高振实密度圆饼状LiFePO4/C的制备及电化学性能

摘要

The cake-like LiFePO4 is synthesized through a solvothermal method with ethylene glycol as the solvent.After that,the LiFePO4 precursor and glucose are mixed and calcined in an reduced atmosphere to obtain the LiFePO4/C composite with a high tap density of 1.3 g· cm-3.The LiFePO4/C samples were characterized by X-ray diffraction,scanning and transmission electron microscopies,whose results demonstrate that the cakelike LiFePO4/C consists of single-crystalline LiFePO4 nanoplates.Additionally,an amorphous carbon layer is evenly coated on LiFePO4.The electrochemical properties of the cathode material LiFePO4/C indicate that it possess a high charge/discharge specific capacity (the initial discharge capacity reach to 157.7 mAh·g-1 at 0.1C) and good cycle stability (82.4％ of capacity retention at 1C after 500 cycles).%以乙二醇为溶剂,采用溶剂热法一步合成圆饼状LiFePO4,然后以葡萄糖为碳源与合成的LiFePO4前躯体高温烧结得到碳包覆的LiFePO4/C复合材料,其振实密度高达1.3 g·cm-3.采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对LiFePO4/C复合材料进行了物相和形貌表征,研究结果表明制备得到的LiFePO4呈圆饼状,且生成的圆饼是由单晶LiFePO4纳米片堆积而成.此外,LiFePO4颗粒表面碳层包覆均匀.将制备的LiFePO4/C用作锂离子电池正极材料,电化学性能测试表明其具有高的充放电比容量(在0.1C时放电,其初始放电比容量为157.7 mAh· g-1)与良好的循环性能(500次循环后容量保持率为82.4％).