Selective Lithium Recovery from Spent NCM811 Cathodes via MnSO4-Assisted Rapid Thermal Reconstruction and Water Leaching

The increasing generation of spent Ni-rich layered cathodes creates an urgent demand for efficient lithium recovery and value-added reutilisation of transition-metal components. An MnSO4·H2O-assisted rapid thermal reconstruction route coupled with water leaching was developed for selective lithium recovery from spent NCM811 cathodes. At an MnSO4·H2O-to-NCM811 mass ratio of 0.9:1, an applied current of 30 A, and a treatment duration of 20 s, the layered structure was converted into water-soluble lithium sulfates and transition-metal-rich oxides. Water leaching at 20 °C for 20 min achieved a stage lithium-leaching recovery of 99.12%, with limited dissolution of Ni, Co, and Mn. The combined aqueous stream contained 0.42 g L−1 Li. After concentration and CO2 carbonation, Li2CO3 was obtained with a precipitation efficiency of 90.6% and a purity of 99.52 wt.%, corresponding to an overall lithium recovery of 88.7%. Elemental-balance closures were 98.6–99.6% for Li, Ni, Co, Mn, and S. The regenerated cathode LiNi0.54Co0.07Mn0.39O2 delivered 95.2 mAh g−1 after 150 cycles at 0.2 C. These results demonstrate integrated lithium recovery and transition-metal reutilisation from spent Ni-rich cathodes.