Non-thermal pretreatment in battery recycling: Dimethyl-sulfoxide leaching of NMC black mass for effective PVDF removal and recovery

Dimethyl-sulfoxide (DMSO) is emerging as an alternative solvent for cathode slurry production, offering lower toxicity compared to commonly used reagents like N-methyl-2-pyrrolidone (NMP). In battery recycling operations, thermal pretreatment is often required for efficient removal of polyvinylidene fluoride (PVDF) binder, which facilitates downstream processes such as flotation and mineral acid leaching. DMSO leaching of black mass offers a solvent-based approach to reverse the slurry production process by dissolving and removing the binder of the battery cathode (PVDF), instead of applying temperature intensive process. This method has the potential to simplify subsequent recycling steps, such as flotation, by eliminating the need for thermal treatments. This study demonstrates the effectiveness of DMSO as a non-thermal-pretreatment for NMC black mass by selectively dissolving PVDF binder and electrolyte residues without additionally impacting the transition metal content. DMSO leaching at a solid-to-liquid ratio of 100 g/L, 80 °C, and 30 min achieved 89.46% F − removal, within the investigated ranges of 40–80 °C and 30–120 min. Subsequent water leaching of soluble fluorine species increased the accumulated removal to a maximum of 95.27 %. The process enables efficient fluorine removal from end-of-life black mass, avoids toxic off-gas emissions, and supports a circular flowsheet through solvent and binder recovery. • End-of-life NMC black mass leached with DMSO as a non-thermal pretreatment method for removal and recovery of PVDF Binder. • Up to 96.86% fluorine removal, indicating effective extraction of PVDF binder and electrolyte residues. • Selective dissolution of PVDF binder and organic battery solvents; no loss of valuable metals (Ni, Co, Mn). • Enables PVDF recovery by anti-solvent crystallization with H 2 O. • Proposed flowsheet integrates DMSO leaching, vacuum drying, and solvent recovery, eliminating the high-temperature steps.