Direct NCA Cathode Active Materials Recycling from Spent Li-Ion Batteries: Solvent-Free Recovery and Healing by Heat Treatment

Abstract

The steadily growing lithium-ion batteries (LIBs) market brings the critical question of the future treatment of tremendous waste from end-of-life (EoL) LIBs. Therefore, recycling of EoL LIBs has become an urgent need to overcome the foreseen environmental and economic challenges. Herein, we propose a direct recycling process to regenerate NCA cathode active material (CAM) from spent LIBs. A gentle heat pretreatment at a low temperature is applied to facilitate the recovery of the CAMs. The cathode strips from EoL LIBs were subjected to two temperatures (150 or 250 °C) during a short time (2 h) to deactivate the strong bonding between the polyvinylidene difluoride binder and the Al current collector surface. Thus, the CAM is easily and fully reclaimed from the Al foil. Moreover, the developed procedure preserves the integrity of the NCA structure without any morphological changes. The full restoration of NCA-based CAM powder is successfully achieved through Li-replenishing using Li₂CO₃ under O₂ atmosphere at different sintering temperatures (750 or 900 °C). The healed NCA CAMs demonstrate decent electrochemical performance including good cyclability and rate performance in NCA//Li half-cell and NCA//LTO full-cell configurations.