Li_2FeSiO_4/C复合材料的制备及电化学性能

Synthesis and Electrochemical Performances of Li_2FeSiO_4/C Composite Materials

以CH3COOLi、FeC2O4、纳米SiO2为原料,葡萄糖为碳源,超导碳为微波耦合剂,采用微波加热法合成了Li2FeSiO4/C材料。考察了不同微波时间对材料室温下电化学性能的影响,并通过X射线衍射、扫描电子显微镜、透射电子显微镜和X射线能谱对样品的晶型结构、表面形貌和组成进行表征分析。结果表明,微波合成法可以快速制备Li2FeSiO4/C材料,微波时间16min所得样品具有最好的电化学性能。室温下以C/16倍率进行充放电测试,放电容量为111.5mA·h/g;以0.2C进行充放电循环,首次放电容量为96.7mA·h/g,19次循环后容量仍有95.2mA·h/g。

In this study,Li2FeSiO4/C composites were prepared by a microwave method,with CH3COOLi,FeC2O4and nanoSiO2as the starting materials,glucose as the carbon source and super-P carbon as the microwave coupling agent.The effects of microwave time on the electrochemical properties of Li2FeSiO4/C were studied at room temperature and the crystal structure, surface morphology and composition were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscope and energy dispersive spectrometer.The results show that Li2FeSiO4/C composites with high performance are quickly and successfully synthesized by the microwave method.Samples with the best electrochemical performance are obtained when the microwave time is 16min.The discharge specific capacity of the obtained sample delivers 111.5mA·h/g at C/16 rate.When charge-discharge cycling at 0.2C,the specific discharge capacity is 96.7mA·h/g and after 19cycles the discharge capacity maintains 95.2mA·h/g.