Discovery of Emerging Fluorinated Organophosphorus Esters Emitted from Spent Lithium-Ion Battery Recycling

The rapid growth of lithium-ion battery (LIB) recycling has raised concerns about the release of new fluorinated contaminants. Here we provide the first field evidence that spent LIB recycling is a source of emerging fluorinated organophosphorus esters (FOPEs) in the indoor environments of recycling facilities. Seven fluorinated organophosphonate, phosphite, and phosphate esters, commonly used as flame-retardant electrolyte additives, were targeted for analysis in indoor dust samples (n = 66) collected from an industrial-scale spent LIB recycling plant in China. Using a targeted UPLC-MS/MS method, all seven FOPEs were detected, with total concentrations ranging from 23.4 to 4780 ng/g (median, 738 ng/g; mean, 917 ng/g). Tris(2,2,2-trifluoroethyl) phosphite was the dominant congener, contributing 50.4% of the total FOPEs, followed by tris(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite and bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl) phosphonate. Correlation analysis suggested shared LIB-related sources and possible phosphite-to-phosphate transformations during battery aging or recycling. Screening-level property predictions further indicated notable persistence, mobility, and bioaccumulation potentials for several highly fluorinated congeners. These findings point to an emerging class of fluorinated contaminants associated with battery circularity with potential implications for the surrounding environment.