Regeneration of Single-Crystal LiNi _0.5 Co _0.2 Mn _0.3 O ₂ Cathode Materials from Spent Power Lithium-Ion Batteries

Efficient and environmentally-friendly methods are needed to recycle spent power lithium-ion batteries. In this research, a simple solid-state method without secondary pollution is used to directly recover the cathode material from spent power lithium-ion batteries. The recycled LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (S-LNCM) crystal cathode material was activated by high-energy ball-milling after pre-heating to remove C and F elements derived from the electrolyte. In situ high-temperature XRD was used to explore the crystal regeneration process of the recycled materials during sintering. The XRD refinement results and TEM images indicated that serious cation mixing was reduced, and phase transitions on the surface of the spent material restored its layered structure. XAFS spectra showed that the coordination structure of the regenerated materials was almost the same as that of a commercial material. The first discharge capacity of the regenerated materials (LNCM-950, 140 mAh g ⁻¹ , 0.2 C) was much higher than that of the spent materials (10 mAh g ⁻¹ , 0.2 C), and the cyclic stability (97%) was higher than that of the commercial material (91%) at 0.2 C after 50 cycles. These results show that simple solid-state method combined with high-energy ball-milling can be used to easily repair the crystal structure and electrochemical performance of spent LiNi _0.5 Co _0.2 Mn _0.3 O ₂ material.