Solvents and Additives Analysis in Lithium Battery Electrolytes Using the Agilent 8850 GC System and Applying It to Real Samples

Importance of the Topic

The composition of lithium-ion battery electrolytes directly influences energy density, cycle life, safety and performance. Accurate quantification of organic carbonate solvents and functional additives is critical for research, quality control and optimization in both battery development and manufacturing environments.

Study Objectives and Overview

This application note describes the development and validation of a gas chromatography method with flame‐ionization detection (GC/FID) on an Agilent 8850 system. Key aims were to establish calibration curves for 13 target compounds, assess linearity, repeatability and limits of detection, and evaluate system robustness when analyzing undiluted real electrolyte samples with high acidity and salt content.

Methodology and Instrumentation

Mixed standard solutions of 13 analytes were prepared in dichloromethane at concentrations from 10 to 500 mg/L. Calibration curves were built over six concentration levels. Real electrolyte samples (pH ~1) were diluted from 5× to 1,000× to fall within the calibrated range. An Agilent 8850 GC with split/splitless inlet and FID was used. Temperature programming from 40 °C to 240 °C enabled baseline separation of all analytes. Repeatability, limits of detection (LODs) and quantification (LOQs) were determined according to standard signal-to-noise criteria.

Used Instrumentation

• Agilent 8850 Gas Chromatograph with split/splitless inlet
• Flame‐ionization detector (FID)
• J&W DB-1701 column (30 m × 0.25 mm, 0.25 μm)
• Helium carrier gas, constant flow mode
• Agilent OpenLab CDS software, version 2.7

Key Results and Discussion

Calibration curves for all 13 analytes exhibited excellent linearity (R2 ≥ 0.999). Intra-day repeatability yielded area RSDs between 0.24% and 2.19% and retention time RSDs below 0.014%. LODs ranged from 0.04 to 0.43 mg/L and LOQs from 0.12 to 1.43 mg/L, demonstrating high sensitivity. Quantitative analysis of two real samples required individual dilution ratios to bring specific analyte concentrations within range. Direct injection of undiluted samples caused peak tailing, retention time shifts and column deterioration. In contrast, 100× diluted samples maintained stable performance over 414 injections, with peak area RSDs below 2.5% and retention time RSDs under 0.03%.

Benefits and Practical Applications

• The GC/FID method is simple, cost-effective and user-friendly for routine electrolyte analysis.
• High sensitivity and precision support both research and quality assurance workflows.
• Strategic sample dilution protects column and inlet consumables, extending operational lifespan.

Future Trends and Opportunities

Advancements may include automated sample handling, integration with mass spectrometry for broader compound identification, micro-GC formats for rapid on-site testing, and real-time monitoring of electrolyte aging and contamination. Emerging electrolyte chemistries and novel additive classes will drive further method development.

Conclusion

The validated Agilent 8850 GC/FID method provides reliable, reproducible quantification of key carbonate solvents and additives in lithium battery electrolytes. Proper sample dilution ensures long-term system stability and extends consumable life, making this approach well suited for high-throughput and routine analytics.

References

1. Yuan ZQ, Feng S. Determination of Carbonate Solvents and Additives in Lithium Battery Electrolyte Using the Agilent 5977B GC/MSD. Agilent Technologies Application Note 5991-9356EN, 2018.
2. Shang HT, Zhang JQ. Determination of Carbonate Solvents and Additives in Lithium Battery Electrolyte With the Agilent 8860 Gas Chromatography System. Agilent Technologies Application Note 5994-5959ZHCN, 2023.