Flexible direct regeneration of heterogeneous cathode materials of spent lithium-ion batteries at industrial scale

ABSTRACT Direct recycling has emerged as a promising alternative to existing recycling methods due to its simplicity and cost-effectiveness. However, its scalable application remains a subject of debate, primarily due to the complexity of mixed degraded cathode materials in practice. The reason is that degraded materials with different compositions are extremely difficult to be repaired to produce cathode materials with uniform composition and performance. Herein, we have successfully realized direct regeneration of mixed heterogeneous degraded LiNi0.5Co0.2Mn0.3O2 from different sources on an industrial scale. First, uniform contact lithiation is achieved through the van der Waals force between Li-1-methyl-2-pyrrolidinone and LiNi0.5Co0.2Mn0.3O2 molecules, leaving them in a uniform lithium-rich state. A self-saturating synthetic lithiation process occurs during subsequent heating, ensuring that each particle from various sources is repaired as needed. This method has been demonstrated to treat 50 kg of cathode materials per batch, and the regenerated products show uniform and excellent performance, achieving a retention rate of 90.7% after 1500 cycles in Ah-level pouch cells. This performance is the best result reported to date and sets a new benchmark for regenerated LiNixCoyMn1-x-yO2 cathode materials, which have reached the standard for direct commercial use.