Resource Recovery and Synthesis of Battery-Grade FePO4 from Waste LiFePO4 Battery Slag

The effective recovery of valuable materials from spent LiFePO4 batteries is crucial for resource sustainability and environmental protection. This study investigates the recovery of phosphorus iron slag from waste LiFePO4 batteries, focusing on dissolution and impurity removal processes to produce battery-grade iron phosphate. Using high-temperature-activated dissolution, followed by precipitation/dissolution for impurity removal, we optimize conditions to ensure high recovery rates (up to 98.8% for FePO4 under optimized conditions) and product purity. Our findings demonstrate that the proposed method effectively transforms waste slag into valuable iron phosphate, significantly reducing raw material costs and contributing to sustainable battery recycling practices. The regenerated LiFePO4 cathode exhibits excellent electrochemical performance, achieving a discharge capacity of 160.7 mAh g−1 at 0.1 C, which meets market standard levels. This research provides a solid foundation for enhancing resource utilization and advancing circular economy principles in the battery industry.