Direct Recycling of Nickel-Cobalt-Manganese-Based Cathode Active Materials from Lithium-Ion Battery Manufacturing Scrap Using a Dry Grinding and Classification Process

Abstract

Recently, direct recycling has gained attention as an environmentally friendly and cost-effective lithium-ion battery (LIB) recycling process. This technology focuses on recycling cathode active materials (CAMs) from spent LIBs or manufacturing scrap. In this study, we investigated the direct recycling of CAMs recovered from manufacturing scrap using a dry grinding and classification process, with dried cathode composite materials used as experimental material. In the grinding process, a jaw crusher was used for primary grinding, followed by a stirred media mill for secondary grinding. Particles under 32 µm were classified into three fraction size groups (coarse, medium, and fine) using an elbow-jet air classifier. Thermogravimetry differential thermal analysis and scanning electron microscopy confirmed the concentration of polyvinylidene difluoride and carbon powder in the fine-sized fraction. X-ray diffraction showed no degradation of crystallinity during the process. Finally, charge-discharge and cycle tests were conducted on battery cells made from two types of cathode slurry. Cathode Slurry I, prepared by mixing 10 mass% of coarse- and medium-sized fractions, exhibited almost the same battery performance as the original product. Cathode Slurry II, prepared by mixing 10 mass% of fine-sized fraction, along with a higher amount of organic matter, resulted in a higher internal resistance and a 5.3% decrease in initial battery capacity. This study demonstrated the potential for direct recycling of CAMs from manufacturing scrap using a simple grinding and classification process.