有机碳源包覆磷酸铁锂正极材料改性研究

Study of Modification of Lithium Iron Phosphate Cathode Materials by Different Organic Carbon Sources Coating Modification

以Fe2O3为Fe源、LiH2PO4为Li源和P源、分别以聚乙烯醇(PVA)、淀粉、柠檬酸为碳源,采用液相分散混合、雾化造粒及高温固相处理工艺制备得到碳包覆的磷酸铁锂正极材料(LiFePO4/C),考察不同有机碳源包覆改性对磷酸铁锂正极材料物理及电化学性能的影响。结果表明:以聚乙烯醇包覆制备的LiFePO4/C材料的首次放电比容量为153.8 mAh/g,首次效率大于90%,材料物相纯正,颗粒呈类球形均匀分布、无团聚现象;淀粉包覆的样品的比容量稍低,为144.4 mAh/g,柠檬酸包覆的产物的比容量最低,为139.4 mAh/g。

Using Fe2O3 and LiH2PO4 as raw materials, and polyvinyl alcohol （PVA）, starch, citric acid as carbon source, respectively, the LiFePO4/C composite materials were prepared by a liquid phase mixing , spray granulation and high temperature solid phase process.The effects of different organic carbon source coating modifications on the physical and electrochemical properties of LiFePO 4/C cathode materials were investigated.The LiFePO4/C material coated by PVA had an initial discharge capacity of 153.8 mAh/g, and the first efficiency greater than 90%, while it had a pure phase , well-distributed spherical particles without agglomeration.However , the sample coated by starch had a lower capacity of 144.4 mAh/g and the citric acid coated sample only had a capacity of 139.4 mAh/g.