工业级硫酸亚铁制备高性能磷酸铁锂正极材料

Preparation of High Performance Lithium Iron Phosphate Cathode Material from Industrial Grade Ferrous Sulfate

工业级硫酸亚铁通过提纯除杂、氧化后与磷酸铵反应生成磷酸铁,磷酸铁与碳酸锂在高温条件下碳热还原烧制成磷酸铁锂正极材料。制得的磷酸铁锂具有优异的电化学性能,0. 1 C放电比容量达到164 mAh·g^-1以上,1 C循环30次后放电比容量仍然稳定在130 mAh·g^-1左右。合成磷酸铁母液通过蒸发浓缩得到硫酸铵、磷酸铵混合物,混合物中氮含量达到14%以上,磷含量达3%以上,可用作氮磷复合肥。

Industrial grade ferrous sulfate after impurity removal and oxidation reacts with ammonium phosphate to form iron phosphate. Iron phosphate and lithium carbonate were used to form lithium iron phosphate by carbothermal reduction method. The obtained lithium iron phosphate had excellent electrochemical performance. The discharge capacity reached 164 mAh·g^-1 or more at 0.1 C rate, and the discharge capacity was still stable at about 130 mAh·g^-1 after 30 cycles at 1 C rate. The mother liquor of synthetic iron phosphate was concentrated by evaporation to obtain a mixture of ammonium sulfate and ammonium phosphate. The nitrogen content of the mixture was more than 14%, and the phosphorus content was more than 3%, which can be used as a nitrogen-phosphorus compound fertilizer.