磷酸铁锂的湿法合成工艺研究

Wet Synthetic Technology Research of LiFePO_(4)

本文采用3种工艺制备磷酸铁锂,研究了不同工艺对产物的物相组成、形貌和杂质含量的影响。以硫酸亚铁、磷酸和氢氧化锂为原辅料,采用水热法制备的纯相磷酸铁锂,形貌呈不规则团聚体,颗粒大小不均匀;用氢氧化钠替代部分氢氧化锂,采用改进的水热法制备的磷酸铁锂,整体一次粒子较常规法大,尺寸较一致,产品钠含量高;以硝酸铁为铁源,用磷酸和氢氧化锂调配液相成分,经固相法还原煅烧制备的碳包覆的磷酸铁锂,形貌为类球形,多数一次粒子尺寸约为500nm,颗粒大小较均匀。

LiFePO_(4) was prepared via three different wet synthetic technology,the influence of different technology on phase composition,morphology and impurity content was investigated.Pure phase LiFePO_(4) cathode material was synthesized from ferrous sulfate,phosphoric acid and lithium hydroxide by hydrothermal synthesis.Morphology of the as-prepared sample was irregular agglomerated particles with uneven size.Modified hydrothermal synthesis was studied by NaOH replacing LiOH,the as-prepared sample was also pure phase LiFePO_(4) with even size,primary particle size was larger than that of conventional hydrothermal synthesis,and the impurity of Na content was higher.Carbon coated LiFePO_(4) with spherical-like particles was synthesized by liquid-solid method,and particle-size distribution was uniform with primary particle size was 500nm.