废旧锂电池回收中电还原浸出与钝化协同机制研究

Recovery of valuable metals in spent lithium ions batteries become an important issue because of its massive scrap, rich rare metals and serious environmental pollution. But hydrometallurgy process also suffers greatly from the complicated flow of two steps, a serious pollution of pretreatment and use of chemical reductant, which has not been solved. Therefore, the project will make full use of SECM, XPS, SEM, AUTOLAB, etc.to clarify the related electrochemical process. the aim of this project is to explore the collaboration-interaction of cathode materials leaching and Al-foil deactivation during the electroreduction leaching process. Then make use of laws of binder influence and small surface leaching to make the leaching system of one step electroreduction for positive plate. The research content of the project is not only conducive to grasp the common laws of leaching system of one step electroreduction but also beneficial to promote the practice use of recovery of spent lithium ions batteries.

废旧锂离子电池数量巨大，且蕴含丰富稀缺资源，同时环境污染问题严重，科学有效地回收其中有价金属已成为重要课题。然而，两步流程复杂、预处理污染大、需化学还原剂是现有湿法流程面临的主要问题。本项目拟采用SECM、XPS、SEM、电化学工作站等测试方法，研究正极材料电还原浸出的热力学、关键控制因素、界面反应和铝箔钝化的热力学、钝化控制方向，阐明正极材料浸出与铝箔钝化的内在协同机制。最后结合粘结剂影响及正极片表面微观浸出规律，构建选择性佳、浸出指标高的正极片一步电还原浸出体系。本项目的实施，有利于明确、掌握正极片有机酸一步电还原选择性浸出机制及规律，同时为废旧锂离子电池回收的研究和应用提供新思路。

随着“双碳”目标和新能源储能产业的迅速发展，废旧锂离子电池回收利用具有环境保护、节约资源等重要意义。针对废旧电池中极片多步分离复杂、药剂成本高等瓶颈问题，本项目构建了选择性佳、浸出指标高的正极片一步电还原浸出新技术，研究正极材料电还原浸出的热力学、关键控制因素、界面反应和铝箔钝化的热力学、钝化控制方向，阐明正极材料浸出与铝箔钝化的内在协同机制。结果表明，在DL-苹果酸2.5mol/L，槽电压8V和温度70℃、120min条件下，锂的浸出率为98.12%，钴的浸出率为97.36%，Al的溶出率仅为6.85%。动力学分析表明，电解浸出过程受化学反应控制，电解浸出Co的Ea值为17.44kJ/mol。再生钴酸锂材料，具有优异的循环性能和倍率性能。本项目提出电化学浸出与再生理论可为废旧电池材料高效低碳循环利用提供理论参考和技术支撑。