Identification of Electrolyte Salts in Lithium-Ion Battery Black Mass

Based on ion chromatographic and thermal analyses, it was demonstrated that the assumption that the presence of PF6– ions in lithium-ion battery (LIB) black mass is due to LiPF6 residues is incorrect. In the industrial samples investigated, PF6--containing residues were present in the case of low temperature-pretreated LIB black mass. Based on thermal analysis, a significant proportion of the PF6- species was found to originate from NaPF6. The presence of NaPF6 is due to the use of tap water in the commercial workup process. Due to the transformation of the PF6- species and the associated changes in degradation and hydrolysis behavior, appropriate recycling routes need to be adapted regarding the handling of the conducting salt.