废旧磷酸铁锂电池回收制备磷酸铁锂材料的试验研究

Experimental Study on the Preparation of Lithium Iron Phosphate Materials by Recycling Waste Lithium Iron Phosphate Batteries

本研究提出一种新的废旧磷酸铁锂电池回收方法,通过还原酸浸-沉淀-固相再生,解决传统湿法冶金的问题。试验结果表明,磷酸浓度2.0 mol/L、固液比70 g/L、反应温度70℃、反应时间120 min的最优条件下,Li^(+)和Fe^(2+)浸出率分别为98.1%和98.0%;pH为6.5时,制备的沉淀产物Fe、P摩尔比为1.50∶1.00,它为纯度较高的Fe_(3)(PO_(4))_(2)·8H_(2)O;Fe_(3)(PO_(4))_(2)·8H_(2)O可作为前驱体来制备LiFePO_(4)正极材料,其电化学性能出色,而充放电倍率(C)可以反映电池容量大小和充电设备能耗,0.1C下首次放电比容量为139.9 mA·h/g,1C循环200次后容量保持率为97.0%。

This study proposes a new method for recycling waste lithium iron phosphate batteries,which solves the problems of traditional wet metallurgy by reducing acid leaching-precipitation-solid phase regeneration.The experimental results show that under the optimal conditions of phosphoric acid concentration of 2.0 mol/L,solid-liquid ratio of 70 g/L,reaction temperature of 70℃,and reaction time of120min,the leaching rates of Li^(+)and Fe^(2+)are 981%and 98.0%,respectively when the pH is 6.5,the prepared precipitate product Fe-P molar ratio is 1.50:1.00,which is Fe_(3)(PO_(4))_(2):8H_(2)0 with high purity;Fe_(3)(PO_(4))_(2)·8H_(2)O can be used as a precursor to prepare LiFePO_(4)cathode materials,with excellent electrochemical performance,while the charge discharge rate(C)can reflect the battery capacity and charging equipment energy consumption,and the first discharge specific capacity at 0.1C is 139.9 mA·h/g,and the capacity retention rate after 200 cycles at 1C is 97.0%.