Pyrolysis gas chromatography - high resolution Orbitrap mass spectrometry as a tool for Li-ion battery shred material forensics

Significance of the topic

Efficient recycling of lithium-ion batteries (LIBs) is essential to secure critical metal resources and reduce environmental impact. Organic binders in shredded LIB material can hinder the extraction of valuable metals during recycling. Rapid and accurate identification of these polymers supports optimized recovery processes and informs the development of improved binder chemistries for next-generation batteries.

Aims and study overview

This study demonstrates the use of pyrolysis gas chromatography combined with high-resolution Orbitrap mass spectrometry to identify organic binders in LIB shred samples. The focus is on direct analysis of shred material, minimizing sample preparation and leveraging the high mass accuracy and resolution of the Thermo Scientific™ Orbitrap Exploris™ GC 240 system to deliver clear binder fingerprints.

Methodology and Instrumentation

A small amount (0.3–0.5 mg) of industrial LIB shred was analyzed without pretreatment. Key instrumentation and operating parameters included:

• Frontier Laboratories™ Multi-Shot Pyrolyzer with Auto-Shot Sampler: two-step thermal program (200 °C desorption for electrolyte removal, 600 °C pyrolysis for binder fragmentation).
• Thermo Scientific TRACE 1610 GC with TraceGOLD™ TG-5SilMS column (30 m × 0.25 mm × 0.25 µm) and a split injection (split ratio 200, injector 300 °C).
• Orbitrap Exploris GC 240 MS: electron impact (EI) and positive chemical ionization (PCI) with methane reagent gas; full scan 30–500 m/z at 60 000 resolving power; internal lock masses for sub-5 ppm mass accuracy.

Main results and discussion

Pyrolysis of polyvinylidene fluoride (PVDF) yields characteristic fluoroalkene markers such as 1,1,3,3-tetrafluoroallylium (C3HF4+, m/z 113.0009). High-resolution extracted ion chromatograms (EICs) eliminated isobaric interferences seen at unit mass resolution, enabling unambiguous PVDF detection. Styrene butadiene rubber (SBR) binders were identified through aromatic pyrolysis products (e.g., toluene, m/z 92.0621) with improved selectivity under 5 ppm accuracy. Switching between EI and PCI without venting (NeverVent technology) allowed confirmation of molecular ions and fragment identities while maintaining system readiness.

Benefits and practical applications

• Direct shred analysis without complex sample prep reduces turnaround time.
• High mass resolution and accuracy simplify fingerprint matching and eliminate matrix interferences.
• Minimal sample consumption lowers system maintenance by reducing corrosive byproducts.
• Rapid switching between ionization modes offers both structural elucidation and fingerprint screening.

Future trends and applications

Ongoing developments may include integration of machine learning for automated binder classification, expansion to emerging binder chemistries, inline pyrolysis-GC-MS monitoring in recycling plants, and deeper investigation of polymer degradation pathways to inform battery design.

Conclusion

The combination of pyrolysis GC and Orbitrap high-resolution MS provides a robust, sensitive, and selective approach for identifying organic binders in LIB shred material. This methodology enhances recycling process control, supports material forensics, and can be adapted to evolving polymer formulations.

References

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3. Peschel, C.; van Wickeren, S.; Preibisch, Y.; Naber, V.; Werner, D.; Frankenstein, L.; Horsthemke, F.; Peuker, U.; Winter, M.; Nowak, S. Comprehensive Characterization of Shredded Lithium-Ion Battery Recycling Material. Chem. Eur. J. 2022, 28, e202200485.
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