Impact of Al and Cu Current Collectors on Li-Ion Battery Recycling

High Resolution Image Download MS PowerPoint Slide The widespread adoption of Li-ion batteries has created a pressing need for effective recycling strategies. A common approach involves producing “black mass”─a mixture of shredded electrode materials─followed by thermal treatment to simplify downstream recovery. Although current collectors (Al and Cu foils) are assumed to be physically separated before pyrolysis, industrial separation is often incomplete, leaving residual foil fragments that can chemically react with cathode materials. Here we investigate the influence of these foils on black mass pyrolysis using simplified model systems composed of pristine LiNi 0.8 Mn 0.1 Co 0.1 O 2 and current collector fragments under inert, mildly oxidizing, and reducing atmospheres. Cu foils were found to form lithium copper oxides, LiCuO and Li 2 CuO 2, previously unreported in the Li-ion battery recycling literature. Al foils produced γ-LiAlO 2, Li 5 AlO 4, and LiAl 2 (OH) 7 ·2H 2 O. The two latter phases readily decompose to γ-LiAlO 2, a compound that has been suggested to be detrimental for Li recovery due to its low solubility. We assess the leaching implications of these product phases, with particular attention to γ-LiAlO 2, to establish that they readily dissolve in dilute H 2 SO 4 /H 2 O 2 solutions, but can reduce Ni and Co leaching efficiency in more realistic black mass mixtures.