A Low‐Cost and Acid‐Free Strategy for Recovering Battery‐Grade Li ₂ CO ₃ From Retired Lithium Metal Batteries

Lithium metal batteries (LMBs) are regarded as one of the most promising technologies for overcoming the energy density limitations of lithium‐ion batteries. In addition to their industrial potential, LMBs are extensively used in laboratories as benchmark systems for evaluating electrode materials, leading to a growing number of retired LMBs. The number of retired LMBs is expected to increase dramatically with future large‐scale commercialization. However, recycling technologies for retired LMBs remain largely unexplored. In this study, an environmentally friendly and cost‐effective recycling process for retired LMBs is developed. The entire process operates without any external chemical additives, inherently enabling low‐cost operation. Moreover, the reaction byproducts can be safely collected or treated, resulting in near‐zero discharge of liquid and gaseous wastes and thus minimizing environmental risks. The recovered battery‐grade Li ₂ CO ₃ was further used to resynthesize LiFePO ₄ and the resulting material exhibited electrochemical performance comparable to that of commercial counterparts. This work fills an important gap in LMB recycling and provides technical support for the sustainable development of high‐energy‐density LMBs throughout their full life cycle.