Eutectic Molten Salt-Assisted Upcycling of Spent Low-Nickel Cathode Materials into High-Nickel Cathode Materials

The regeneration and utilization of metallic elements in waste lithium-ion batteries (LIBs) have caused growing notice from researchers and battery manufacturers because of the increasing environmental protection pressure and limited lithium resources. In this study, utilizing a ternary eutectic salt system, we present a value-added upcycling approach aimed at transforming spent low-nickel layered oxide cathode materials into high-nickel counterparts. Incorporating NiO additives, this eutectic salt system creates a lithium-rich molten environment that effectively facilitates the diffusion of both lithium ions and transition metal ions. Consequently, this upcycling strategy not only restores the layered structure of the material but also substantially enhances its capacity and cycling stability. The upcycled LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode demonstrates a high capacity of 191.9 mAh g–1 at a current density of 0.1 C. Even after 200 cycles at 1.0 C, the cathode retains a substantial capacity of 109.08 mAh g–1 with a remarkable capacity retention of 61.56%. In summary, our proposed strategy offers a feasible approach to realize the value-added recycling of spent LIBs.