Quick and Easy Material Identification of Salts Used in Lithium-Ion Batteries by FTIR

Significance of the Topic

Rechargeable lithium-ion batteries demand precise identification of electrolyte salts to ensure safety, performance, and reliability in applications from portable electronics to electric vehicles. FTIR spectroscopy provides a nondestructive, rapid approach to raw material verification, minimizing risks associated with hygroscopic, toxic, or combustible lithium salts.

Objectives and Study Overview

This work showcases the use of the Agilent Cary 630 FTIR spectrometer with ATR sampling and MicroLab software to build a spectral library for seven common LIB salts and to verify four unknown salt samples under glove box conditions. The aim is to establish a fast, reliable workflow for both manufacturing QC and R&D environments.

Methodology and Instrumentation

• Instrumentation
  • Agilent Cary 630 FTIR spectrometer with diamond ATR module
  • Measurement parameters: 4,000–650 cm−1 range, 32 background and sample scans, 4 cm−1 resolution, HappGenzel apodization, Similarity search algorithm
• Library Generation
  • Create a user spectral library in MicroLab for Li2CO3, LiCl·H2O, LiCl, LiFePO4, LiTFSI, LiPF6, LiBF4
• Unknown Sample Analysis
  • Four salts measured in argon-filled glove box using ATR press
  • Automatic library search with hit quality index (HQI) thresholds for confidence

Main Results and Discussion

All four unknown samples were correctly identified with HQI values above 0.985, demonstrating the method’s accuracy. Color-coded results (green for HQI > 0.95) provide immediate, high-confidence confirmation. The Cary 630 FTIR’s compact, robust design and the intuitive MicroLab interface minimize training requirements and user error, making it ideal for glove box workflows.

Benefits and Practical Applications

• Rapid, nondestructive verification of critical battery salts
• Safe operation under moisture-controlled glove box environments
• Automated spectral library management and identification minimize analyst workload
• Color-coded outputs support quick decision-making in QC and R&D

Future Trends and Opportunities

• Extension of spectral libraries to next-generation electrolyte salts
• Integration with laboratory information management systems for end-to-end traceability
• On-line deployment in battery production lines for real-time QC
• Advanced pattern-recognition and machine-learning approaches for complex mixtures

Conclusion

The Agilent Cary 630 FTIR spectrometer with ATR and MicroLab software delivers a turnkey solution for fast, accurate lithium-ion battery salt identification in glove box conditions. This method supports stringent QC and accelerates R&D in the energy storage sector.

References

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