以磷铁为原料水热法制备电池级磷酸铁的研究

Study on Preparation of Battery Grade Iron(Ⅲ) Phosphate from Ferrophosphorus by Hydrothermal Method

以黄磷所得副产品磷铁为原料,通过湿法溶解、除杂、结晶等工艺制备电池级磷酸铁,然后利用制备出的磷酸铁制备磷酸铁锂。制备电池级磷酸铁的最佳工艺参数为:硝酸浓度为3.0 mol/L、最佳反应温度为110℃、最佳反应时间为120 min、反应体系铁质量浓度为18.0 g/L,此时样品中铁含量与铁磷比接近理论值。LiFePO_(4)/C样品首次充电容量、放电容量、放电的库伦效率分别为158.8 mAh/g、147.8 Ah/g、93.1%,说明磷酸铁锂电化学性能较好,能用于锂电池的正极材料。

The battery grade Iron(III)phosphate was prepared by wet dissolution,impurity removal,crystallization and other processes with the by-product of yellow phosphorus as raw material,and then lithium iron phosphate was prepared from the prepared iron phosphate.The optimal process parameters for preparing battery grade iron(III)phosphate are:nitric acid concentration is 3.0 mol/L,the optimal reaction temperature is 110℃,the optimal reaction time is 120 min,and the iron mass concentration of the reaction system is 18.0 g/L.At this time,the iron content in the sample and the iron phosphorus ratio are close to the theoretical value.The first charge capacity,discharge capacity and discharge coulomb efficiency of LiFePO4/C sample are 158.8 mAh/g,147.8 Ah/g and 93.1%respectively,which indicates that Lithium iron phosphate has good electrochemical performance and can be used as cathode material of lithium battery.