Characterization of Industrial Lithium Iron Phosphate-Based Battery Waste

In recent years, lithium iron phosphate (LFP) battery chemistries, both with and without manganese doping, have become increasingly common in battery applications. As the use of this battery chemistry expands, the number of end-of-life batteries will increase, highlighting the need for efficient recycling methods and knowledge of black mass characteristics. Thus, a comprehensive characterization of industrial lithium iron phosphate-based black mass was conducted. In this study, Li (3 wt %), Fe (12 wt %), P (6 wt %), and Mn (8 wt %) were detected in the black mass. Significant amounts (>1 wt %) of Co and Ni were also found, along with several doping agents (1600 ppm Ti, 1500 ppm V, and 690 ppm Si) and impurities (1400 ppm S). The size fraction with the highest mass after sieving (45 wt %) was 125-224 μm. However, characterization results showed that the particles were mainly agglomerated, and the actual dominant particle size is smaller than 125-224 μm. In smaller sieving size fractions (<125 μm), the carbon had a more graphitic structure, whereas in larger size fractions, the carbon had a lower graphitization degree and more defects, suggesting the presence of polymers. The results suggest high heterogeneity in the industrially provided black mass, highlighting the importance of developing a flexible process for future LFP-based battery recycling facilities.