Contaminations from Lithium-Ion Battery Fires—Per- and Polyfluoroalkyl Substances (PFAS) in Soot

Fluorinated substances are widely used in the different components of the lithium-ion battery cell, such as electrode binders, electrolyte, additives and separator materials. To date, most studies regarding the fluorinated contaminations from lithium-ion battery fires are focused on the gases formed, whereas the solids produced are not as well characterized. Here, we present an experimental study investigating the occurrence of per- and polyfluoroalkyl substances, in soot and particulates formed after thermal runaway in lithium-ion battery cells. Per- and polyfluoroalkyl substances were detected in every battery cell test performed in this study. The concentration of per- and polyfluoroalkyl substances ranged between 20 to 130 ng/g_soot. Extrapolation of data gives an estimated release of 10 to 60 µg of per- and polyfluoroalkyl substances per kg battery cells. Among the 22 per- and polyfluoroalkyl substances analyzed, perfluorobutanesulfonic acid and perfluorobutanoic acid were found in the highest concentrations for all samples. Interestingly, perfluorooctanoic acid was detected in all tests, in concentrations ranging between 0.05 to 0.62 ng/g_soot. These findings are of importance not only for the purpose of decontamination after thermal runaway events, but also when it comes to the lithium-ion battery recycling processes.