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Aufgrund ihrer Persistenz, Mobilität und Toxizität haben per- und polyfluorierte Alkylverbindungen (PFAS) zunehmend an Aufmerksamkeit und Relevanz gewonnen. Mit der PFAS-Belastung von Umweltmatrices ist auch der Bedarf an analytischen Methoden gestiegen. Trifluoressigsäure (TFA) gehört als kürzeste perfluorierte Carbonsäure zur Gruppe der PFAS und gilt als emerging pollutant, dessen Gehalte in der Umwelt zukünftig eine stärkere Überwachung erfordern. Im Vortrag wird zunächst auf die Entwicklung einer sensitiven Analysenmethode zur Bestimmung von TFA in Böden mittels HPLC-MS/MS eingegangen. Anschließend werden die TFA-Ergebnisse von 100 ausgewählten Acker- und Grünlandproben aus Deutschland vorgestellt und diskutiert.
In light of the emerging threat of environmental contamination from per- and polyfluoroalkyl substances (PFAS), there is a growing need for analytical techniques that can be applied to a range of environmental matrices, including water, air, plant, and soil samples. Trifluoroacetic acid (TFA) is a member of the PFAS class, representing the shortest perfluorinated carboxylic acid and is an emerging pollutant whose environmental levels are expected to increase in the future. Soil matrices represent the interface between plant and ecosystem uptake of TFA, but contamination is poorly understood, largely due to a lack of uniform TFA determination methods.
This study compares six ways of determining TFA in soils and highlights their limitations. We present a validated sample preparation method with high recoveries (104 %), low LOD (0.015 ng/g) and LOQ (0.045 ng/g). This approach includes isotope dilution analysis with hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry (HILIC-MS/MS) detection.
The method was applied to quantify the TFA content in 100 soil samples from grassland and farmland across Germany. The results indicate the ubiquity of TFA, accompanied by elevated contamination levels in certain locations. An analysis of variance revealed no correlation with collection site and designation purpose. However, a low correlation was observed with dry bulk density.
In this study, 77 end-of-life (EOL) commercial lithium-ion batteries (LIBs) of different formats were systematically analyzed to investigate electrolyte degradation mechanisms and the influence of pristine electrolyte composition on aging. Comprehensive chemical characterization employed targeted and non-targeted mass spectrometry (MS), combining liquid and gas chromatography (LC-MS/MS, GC-MS) with high-resolution MS (HRMS). This approach identified confirmed pristine components and complex degradation products. Commercial rechargeable pouch and cylindrical cells often deviated from conventional research model systems, using mixed lithium salt anions, ionic liquids (ILs), and high concentrations of triflates, triflimides, and bis(fluorosulfonyl)imide (FSI), functioning as solvents, salts, or additives. Specific IL degradation products and previously unreported pathways were proposed. A novel series of oligomerization products from propylene carbonate (PC) was also identified. In contrast, non-rechargeable coin cells showed prevalent use of per- and polyfluoroalkyl substances (PFAS) in their original electrolytes. Distinct PFAS degradation mechanisms were proposed for the first time. The absence of carbonate oligomers and lithium salt-derived products in coin cells, alongside standard carbonates, suggests lithium counterion coordination critically influences Lewis acid-catalyzed degradation. These findings provide new insight into real-world LIB aging, highlighting differences between commercial devices and model systems.
In this study, 77 end-of-life (EOL) commercial lithium-ion batteries (LIBs) of various formats were systematically analyzed to investigate electrolyte degradation and the influence of pristine electrolyte compositions on aging behavior. Comprehensive chemical characterization was conducted using targeted and non-targeted mass spectrometry (MS), employing LC-MS/MS, GC-MS, and high-resolution MS (HRMS). This integrated approach enabled the identification of confirmed pristine components and complex degradation products. The results show that rechargeable pouch and cylindrical cells often deviate from conventional model systems, containing mixed lithium salt anions, ionic liquids (ILs), and high concentrations of triflates, triflimides, and bis(fluorosulfonyl)imide (FSI). These function as solvents, salts, or safety-enhancing additives. Specific IL degradation products were identified, and hypotheses formulated on previously unreported pathways. Furthermore, a novel series of oligomerization products of propylene carbonate (PC) was detected. In contrast, non-rechargeable coin cells revealed widespread use of per- and polyfluoroalkyl substances (PFAS) in their original electrolytes. Based on ex situ analyses, hypothetical PFAS degradation mechanisms are proposed here for the first time. The absence of carbonate oligomers and lithium salt-derived products, alongside the presence of standard carbonates, indicates lithium counterion coordination as a key factor in Lewis acid-catalyzed degradation. This study offers valuable insights into real-world battery aging.
This study presents a systematic, characterization of electrolytes from commercial lithium-ion batteries (LIB), encompassing 90 batteries from leading global manufacturers across diverse formats and application sectors. An integrated, complementary mass spectrometric workflow combining LC–MS/MS, GC–MS, and high-resolution MS was employed. To ensure robust structural annotation, molecular identifications were assigned confidence levels following Schymanski et al. (2014).
Across all formats, PF6− was confirmed as the dominant Li+ counterion, frequently coexisting with BF4−, PO2F2−, and bis(fluorosulfonyl)imide (FSI−), forming binary and ternary salt systems optimized for both conductivity and safety. Solvent systems revealed the widespread use of propylene carbonate (PC) combined with diverse carbonate mixtures, demonstrating trends in performance optimization specific to cell format. A variety of additives were identified, reflecting a clear shift towards multifunctional, synergistic additive packages and the gradual replacement of fluorinated species with environmentally safer alternatives. Cycling studies demonstrated that electrolyte degradation mechanisms are strongly influenced by electrode composition and additive chemistry, with oxidative degradation pathways dominating.
Together, these findings provide rare empirical insight into the evolving formulation strategies of electrolytes in commercial LIB, still employing classic carbonates and LiPF6, but highlighting a trend toward safer, more robust, and sustainable electrolyte architectures by using synergistic multifunctional systems.
Per- and polyfluoroalkyl substances (PFAS) are well-known as “forever chemicals” and persistent pollutants released by different anthropogenic sources. The potential release of PFAS from accumulating electronic waste and lithium-ion battery (LIB) recycling activities has gained increasing attention in the past years. This creates a need for analytical methods tailored for the determination of PFAS out of environmental matrices related to the named activities or directly out of the concerned materials. In this work, analytical strategies for the monitoring of PFAS in LIB recycling materials were explored for a group of legacy perfluoro sulfonic- and carbonic acids (PFSA and PFCA) and of fluorinated sulfonylimides suspected to be LIB electrolyte ingredients. These analytical strategies comprehend PFAS target approaches with a herein optimized liquid chromatography tandem mass spectrometry (LC–MS/MS) method equipped with a HILIC (hydrophilic interaction liquid chromatography) column in combination with the TOP (total oxidizable precursor) assay and an adapted sample preparation method for high-matrix LIB recycling materials. The validated target method was applied to a set of LIB recycling materials: end-of-life batteries, black masses from hydrometallurgical recycling, and gas absorption solutions from thermal treatment of black masses as part of the recycling procedure. Investigation results show that the LIB industry can be connected to the release of both “LIB”-PFAS, such as the target sulfonylimides, and “already-legacy” PFAS, like the PFSA and PFCA. Especially, the presence of trifluoroacetic acid (TFA) as an emerging pollutant in every investigated LIB material type underlines the threat of PFAS emissions from LIB waste and recycling activities.