Comprehensive characterization of lithium carbonates recovered from different spent lithium-ion batteries black masses

Abstract The growing demand for electric vehicles has intensified the need for efficient recycling of lithium-ion batteries (LIBs) to recover critical materials. This work investigates the recovery and detailed characterization of Li 2 CO 3 samples recovered from two different types of black masses (BM) derived from spent NMC 622 batteries. Structural, morphological, and compositional analyses were carried out using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman Spectroscopy (RS), and X-ray Microanalysis (EDX). The obtained results reveal that pretreatment of the starting black mass significantly influences the impurity content and crystalline structure of the recovered samples. The sample from thermally-pretreated BM exhibited higher purity and fewer secondary phases than those from mechanical-pretreated BM, where compounds such as Li 2 SO 4 , LiAl 2 (OH) 6 ·H 2 O, LiF, and LiOH were detected. Morphological differences correlated with the presence of impurities impacting crystal growth. These findings provide valuable insights for optimizing pretreatment and purification routes, thereby improving the quality of recycled Li 2 CO 3 for battery manufacturing and supporting circular economy strategies in the LIB sector.