Analysis of Carbonate Esters and Additives in Battery Electrolyte Using Agilent 8860 GC

Importance of the Topic

As the market for lithium-ion batteries expands to power electric vehicles and grid storage, accurate analysis of electrolyte components is critical. Carbonate esters and functional additives determine performance, cycle life, and safety of cells. Reliable quantification supports quality control, research on new formulations, and regulatory compliance.

Objectives and Overview

This study describes the development of a rapid and cost-effective gas chromatography method for simultaneous analysis of thirteen common carbonate solvents and additives in battery electrolytes. Using an Agilent 8860 GC with flame ionization detection, the method aims to achieve baseline separation within 14 minutes, high linearity over 10–500 mg/L, low detection limits, and robust repeatability for routine application.

Methodology and Instrumentation

Sample preparation involved 1000× dilution of electrolyte in dichloromethane with external calibration. Calibration standards spanned 10–500 mg/L for all target compounds. Method performance was validated through retention time and peak area repeatability, calibration linearity, limit of detection (LOD), and limit of quantification (LOQ).

Used Instrumentation

• Gas chromatograph: Agilent 8860 GC fitted with split-splitless inlet
• Column: Agilent J&W HP-5ms Ultra Inert, 30 m × 0.25 mm, 0.25 µm film
• Injector temperature: 250 °C, split ratio 20:1, injection volume 1 µL
• Carrier gas: helium or nitrogen at constant flow 1.2 mL/min
• Oven program: 40 °C hold 3 min, ramp 10 °C/min to 160 °C, hold 5 min
• Detector: flame ionization detector, air 400 mL/min, fuel 30 mL/min, makeup 30 mL/min
• Autosampler: Agilent 7650A liquid sampler
• Data system: Agilent OpenLab CDS v2.6

Main Results and Discussion

The method achieved baseline separation of all thirteen analytes within 14 minutes, with earlier elution times when using nitrogen. Calibration curves demonstrated excellent linearity (R2 > 0.9995) across the concentration range. Retention time repeatability was below 0.04% RSD and peak area repeatability below 1.5%. Determined MDLs ranged below 0.5 mg/L and LOQs below 1.6 mg/L. Analysis of seven real electrolyte samples showed clear detection of key esters and additives with response repeatability under 1.5%, confirming method suitability for quality control and formulation analysis.

Benefits and Practical Applications

• Fast analysis time under 14 minutes per run
• High sensitivity and low detection limits
• Excellent repeatability for retention time and peak area
• Cost-effective use of standard GC-FID instrumentation
• Adaptable for routine QC in battery manufacturing and R&D

Future Trends and Applications

Emerging demands for next-generation electrolytes will drive integration of mass spectrometric detection for identification of degradation products, miniaturized GC systems for in-field testing, and application of machine learning for automated peak deconvolution and quantification. Green analytical approaches may introduce alternative solvents and carrier gases to reduce environmental impact.

Conclusion

The presented Agilent 8860 GC-FID method provides a reliable, high-throughput solution for comprehensive analysis of carbonate esters and additives in lithium-ion battery electrolytes. With robust performance and straightforward operation, it supports both routine quality control and advanced research into electrolyte optimization.

Reference

1. Grand View Research. Lithium-Ion Battery Market Size Worth $182.53 Billion by 2030. Grand View Research, Inc., 2022.
2. Hobold G.M. et al. Moving Beyond 99.9% Coulombic Efficiency for Lithium Anodes in Liquid Electrolytes. Nat. Energy 2021, 6, 951–960.
3. Markevich E. et al. Improved Performance of Li-Metal Cathodes and Small Amounts of Electrolyte Solutions Containing Fluorinated Carbonates at 30 °C–55 °C. J. Electrochem. Soc. 2020, 167, 070509.
4. Aurbach D. et al. On the Use of Vinylene Carbonate as an Additive to Electrolyte Solutions for Li-Ion Batteries. Electrochim. Acta. 2002, 47, 1423–1439.
5. Zhiquan Y.; Shuang F. Determination of Carbonate Solvents and Additives in Lithium Battery Electrolyte Using the Agilent 5977B GC/MSD. Agilent Technologies Application Brief, 2018.