A review on direct regeneration of spent lithium iron phosphate: From waste to wealth

Lithium iron phosphate (LFP) batteries are widely used due to their affordability, minimal environmental impact, structural stability, and exceptional safety features. However, as these batteries reach the end of their lifespan, the accumulation of waste LFP batteries poses environmental hazards. Recycling these batteries is crucial for mitigating pollution risks and enabling secondary resource utilization. Traditional metallurgical recycling methods offer limited economic returns for waste LFP batteries due to their relatively low value compared to other types of cathode materials. Therefore, direct regeneration has emerged as a simpler, more cost-effective, and promising alternative. Given the stable crystal structure of LFP after decommissioning, direct regeneration by repairing lithium vacancy defects presents significant potential. This paper critically reviews the research progress on LFP regeneration, particularly focusing on developments over the past five years, and evaluates the industrial feasibility and pros and cons of these methods. Grounded in the concepts of wealth and waste, this paper adopts a novel perspective to discuss the processes of LFP degeneration and regeneration. It examines the dual attributes of waste and wealth in waste LFP batteries, elucidating the relationship and transformation between these two aspects. In particular, the paper discusses the value of LFP in its three forms-new, second-life, and waste-and the environmental and safety impacts of waste LFP batteries. It emphasizes the importance of converting waste into wealth and the role of regeneration as a potential means in the LFP recycling process. The paper objectively assesses the current challenges and opportunities, aiming to provide insights into the importance of LFP battery recycling and to explore potential avenues for advancing regeneration technologies through this comprehensive review.