微波合成法制备锂离子电池正极材料Li2FeSiO4

摘要

We report a novel synthetic route for the preparation of the Li2FeSiO4 cathode material by microwave processing.The Li2FeSiO4 material was synthesized using mechanical ball-milling and subsequent microwave processing.The prepared samples were characterized by X-ray diffraction,manning electron microscopy,and electrochemical methods.Properties of the prepared materials and electrochemical characteristics of the samples were investigated and compared to samples prepared by the conventional solid-state reaction.The obtained results indicated that highly pure Li2FeSiO4 material with uniform and fine particle size was quickly and successfully synthesized by microwave(MW) heating at 650℃ for 12 min.This compound showed high specific capacity and good cycle ability.The initial discharge capacity of the sample obtained by MW heating delivered 119.5 mAh·g-1 at 60℃ at a current density of C/20 rate(1C=160 mA·g-1).After 10 cycles the discharge capacity maintained 116.2 mAh·g-1.The Li2FeSiO4 material displayed higher phase purity,better microstructure,and better electrochemical properties than the sample prepared by the conventional solid-state method.%研究了一种制备锂离子电池正极材料Li2FeSiO4的新方法.采用机械球磨结合微波热处理合成了Li2FeSiO4正极材料.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.与传统固相法合成的材料在晶体结构、微观形貌以及充放电性能方面进行了比较.结果表明,微波合成法可以快速制备具有正交结构的Li2FeSiO4材料;在650 ℃时处理12 min,获得了纯度高、晶粒细小均匀的产物,该产物具有较高的放电比容量和良好的循环性能.在60℃下以C/20倍率(电流密度,1C=160mA·g-1)进行充放电,首次放电容量为119.5 mAh·g-1,10次循环后放电容量为116.2 mAh·g-1.与传统高温固相法相比,微波合成法制备的材料具有较高的纯度、均匀的形貌和较好的电化学性能.