微波碳热还原法合成锂离子电池正极材料Li_2FeSiO_4/C

Synthesis of Li_2FeSiO_4/C cathode materials by microwave carbothermal reduction method

以Li2CO3、FeOOH、纳米Si O2为原料,聚乙烯醇和超导碳为碳源,采用微波碳热合成法合成了Li2FeSi O4/C材料。通过XRD、SEM和恒流充放电测试,对样品结构、形貌和电化学性能进行了表征和分析。结果表明,微波合成法可以快速制备具有正交结构的Li2FeSi O4材料;在处理温度650℃、时间12min的条件下获得了高纯度、晶粒细小均匀的产物,并具有良好的电化学性能。以C/20倍率进行充放电测试,首次放电容量为127.5mAh/g,20次循环后容量仍有124mAh/g。

In this study,preparation of Li2FeSiO4/C composites were accomplished by a microwave carbon thermal reduction method,with Li2CO3,FeOOH and nano-SiO2 as the starting materials,polyvinyl alcohol（PVA） and super-P carbon as the carbon sources.The prepared samples were characterized by X-ray diffractometry,scanning electron microscope,and galvanostatic charge-discharge test.The results show that highly pure Li2FeSiO4 material with uniform and fine particle size is quickly and successfully synthesized at 650℃ for 12min.The initial discharge capacity of the obtained sample delivers 127.5mAh/g at C/20 rate between 4.5 and 1.8V,and after 20 cycles the discharge capacity maintains 121.6mAh/g,indicating good electrochemical capacity and cycling stability.