退役石墨负极粉除杂及修复再生研究进展

Research progress on impurity removal and repair regeneration of spent graphite negative electrode powder

动力电池的服役年限通常为5~8年,达到使用寿命后需进行循环再生。退役电池中富含大量的能源金属和战略元素;其中,负极石墨属于战略矿产元素,在锂离子电池中质量占比达12%~21%,如若不进行妥善处理将造成资源浪费并对环境治理造成压力。本文通过对近期相关文献进行分析,从退役石墨失效机制、除杂方法及修复再生等环节归纳了退役石墨负极粉再利用研究进展。首先从SEI增厚失效、表面枝晶、活性颗粒破裂、集流体腐蚀四个方面系统分析了退役石墨失效机制;其次重点介绍了退役石墨杂质元素高效脱出方法,包括酸碱处理法、低共溶剂浸出法、电解法等;最后从碳材料包覆修复、金属氧化物包覆修复及表面人工界面膜构筑等方面着重阐述了退役石墨修复再利用策略;并对退役石墨发展方向和应用前景进行展望,提出未来退役石墨再生将朝着高值化、低能耗、可持续的方向发展。本文有望为退役动力电池石墨负极资源化利用构筑坚实的理论基础并提供极具价值的选择依据。

Power lithium-ion batteries possess a specific service life,typically around 5-8 years,after which they must be decommissioned.Spent batteries contain a wealth of valuable energy metals and strategic elements.Notably,the graphite from the negative electrode is classified as a strategic mineral element,constituting 12%to 21%of the battery's composition.Without proper handling,it will lead to resource waste and environmental governance pressure.This article summarizes an overview of the recent research progress on the reuse of spent graphite negative electrode powder from three aspects:failure mechanism,impurity removal methods,and repair regeneration.Firstly,the article conducts a systematic anylysis of the failure mechanism of spent graphite,examining four aspects:solid electrolyte interphase thickening failure,surface dendrites,active particle rupture,and collector corrosion;Secondly,the efficient removal methods of impurity ions from spent graphite are emphatically introduced,including acid-base treatment,deep eutectic solvent leaching,electrolysis,etc;Lastly,the article emphasizes strategies for the repair and reuse of spent graphite,including carbon material coating repair,metal oxide coating repair,and the construction of artificial surface interface.The article also discusses the development direction and application prospects of spent graphite,suggesting that future regeneration efforts will focus on high value,low energy consumption,and sustainable practices.It is anticipated that this article will serve as a theoretical foundation and guide for the resourceful utilization of graphite negative electrodes from retired power batteries.