Selective recovery of valuable metals from NCM cathode scraps: A pretreatment-free process

In the recycling of spent lithium-ion batteries, pretreatment is an essential step to separate cathode materials from aluminum current collectors. However, it is typically energy-intensive, with high chemicals consumption and metal loss. In this research, we demonstrate a sustainable and straightforward strategy to acheive stepwise recovery of Li and transition metals without pretreatment step. In a mildly acidic hydrothermal environment, the interaction between aluminum current collectors and cathode materials results in the formation of AlO(OH) interlayers, which preserves the sandwich-like structure of the leaching residue while lithium can be selectively recovered. In the leaching residue, the cathode materials are transformed into a low-valence transition metal hydroxides, which are more easily to be reacted than the passivated aluminum foil and other impure compounds (e.g. binder, TiO 2 and other oxide additives etc.) under mild acidic solutions. As a result, the transition elements i.e. Ni, Co, Mn can be selectively recovered. Therefore, 90.0 % of Li and more than 95.0 % of transition metals are successfully recycled, with Al and other impure compounds being conserved in the leaching residue. This research proves it is possible to achieve selective metal recovery while skiping the pretreatment step and offers new perspectives on the recycling of valuable metals from spent lithium-ion batteries.