Direct recycling is a promising approach for valorizing spent lithium-ion batteries, yet the effect of impurities on cathode regeneration has been insufficiently explored. Herein, an end-of-life LiNi0.6Co0.2Mn0.2O2 (NCM622) pouch cell is used as a model system to systematically investigate the behavior of impurities and the outcomes for regeneration, using XPS, SRD, and XAS techniques. The analysis identifies AlPO4, AlF3, Li3PO4, LiF, LixPFyO4, and Li2CO3 as the main impurities in the spent powder, along with Al-inclusion limited to a surface near region. Among these, Al- and F-containing species are found to significantly affect the regeneration process, inducing further Al- and F-inclusion in the regenerated material, while PO43– species exhibit a minimal structural impact. In-depth structural analysis reveals that F-inclusion proceeds via substitution of lattice oxygen, causing increased structural disorder. Al-inclusion most likely involves epitaxial crystal growth promoted by excess lithium salts, resulting in structural asymmetry at elevated inclusion levels. Electrochemical evaluation shows that low-level impurity inclusion has a negligible effect on initial capacity. Yet, impurity accumulation, potentially amplified over repeated recycling, markedly compromises capacity recovery and structural integrity. This work clarifies impurity-induced effects during regeneration and highlights the importance of impurity control for enabling sustainable and effective direct recycling.
Liu et al. (2026) studied this question.