废旧磷酸钒锂电池材料回收及再利用研究

Spent lithium vanadium phosphate battery material recycling and reusing

针对磷酸钒锂电池材料溶解-沉淀回收困难的问题,采用Na OH溶液浸泡磷酸钒锂电极,溶解集流体铝箔,分析过滤产物中锂、钒、磷和碳的摩尔比,依据分析结果添加Li OH·H2O、V2O5、NH4H2PO4和蔗糖,使过滤产物和添加物的混合物中,锂、钒、磷和碳的摩尔比为3.15∶2∶3∶3,对混合物进行不添加酸和添加盐酸处理,在氩气气氛中于300℃下预烧结4 h,冷却和研磨后,再于氩气气氛中800℃下煅烧12 h,得到磷酸钒锂正极材料。与不经酸处理获得磷酸钒锂相比,X射线衍射(XRD)测试结果表明,经过酸处理工艺获得的磷酸钒锂结晶更好,其衍射峰与单斜结构磷酸钒锂谱图一致;扫描电子显微镜(SEM)测试结果表明,经过酸处理工艺获得的正极材料结晶粒径更小,粒径分布较均匀;能谱分析结果表明,产物中没有残存的氯;电化学测试结果表明,经过酸处理工艺获得的磷酸钒锂首次放电比容量为93.8m Ah/g,50次循环后的容量保持率为98.4%。

Lithium vanadium phosphate electrodes were immersed in NaOH solution to dissolve aluminum foil current collector to solve recycling difficult issues of lithium vanadium phosphate battery material. The molar ratio of lithium, vanadium, phosphorus, carbon in residue was adjusted to 3.15 ： 2 ： 3 ： 3 using Li OH·H2O、V2O5、NH4H2PO4, sucrose respectively. Then the mixture in HCI compared with untreated was immersed. The mixture was presintered at 300℃ for 4 h and sintered at 800 ℃ for 12 h in argon-hydrogen mixtrue atmosphere after grinding. X-ray diffraction pattern shows that the diffraction spectrums of cathode material immersed in HCI is coincided with lithium vanadium phosphate standard spectrums. SEM images show that the cathode material immersed in HCI has smaller and uniform distribution particale size. The lithium vanadium phosphate shows a high initial discharge specific capacity of 93.8 mAh/g, the reversible specific capacities of lithium vanadium phosphate is more than 98.4% of initial capacity at the fiftieth cycle.