Analysis of Carbonate Esters, Additives, and Phosphate Esters in Lithium-Ion Battery Electrolyte Using GCMS-QP2050

Significance of the Topic

The performance, safety and lifetime of lithium-ion batteries depend strongly on the purity and composition of carbonate esters and additives in the electrolyte. Precise qualitative and quantitative analysis of these components and any impurities is essential for R&D, quality control and the development of next-generation energy storage systems.

Objectives and Overview of the Study

This work evaluates the Shimadzu GCMS-QP2050 combined with the AOC-30i auto-injector for high-precision analysis of eight common carbonate esters and additives in lithium-ion battery electrolytes. The study aims to establish calibration linearity, injection repeatability, quantification in real commercial samples, and qualitative identification of unknown impurities.

Used Instrumentation

• Gas chromatograph–mass spectrometer: Shimadzu GCMS-QP2050
• Auto-injector: Shimadzu AOC-30i
• Column: SH-I-5MS (30 m × 0.25 mm I.D., 0.25 μm film)
• Injection: Split mode at 250 °C, split ratio 50
• Carrier gas: Helium at constant linear velocity (40 cm/s)
• Column oven program: 40 °C (3 min) → 10 °C/min to 160 °C (5 min)
• Mass spectrometry: EI source at 200 °C, interface at 230 °C, SIM acquisition for target ions

Methodology

Mixed standard solutions of eight compounds (10–500 mg/L in dichloromethane) were analyzed under SIM mode to construct calibration curves. Repeatability was assessed by five consecutive injections of the 10 mg/L standard. Real commercial electrolyte samples were diluted 1000× in dichloromethane under inert conditions to prevent precipitation and degradation.

Main Results and Discussion

Chromatographic separation of all eight target compounds was achieved with baseline resolution. Calibration curves exhibited excellent linearity (R2 > 0.999) across the concentration range. Repeatability of peak areas showed RSD values below 7% for all analytes. Quantitative analysis of four commercial electrolytes (LiFSI- and LiPF6-based) revealed concentrations of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate and ethylene carbonate consistent with product specifications. In LiPF6-based samples, additional peaks indicated unknown impurities. Low-electron-ionization (14 V) enhanced the molecular ion signal and enabled identification of dimethyl fluorophosphate (DMFP) as a degradation product.

Benefits and Practical Applications

• High analytical precision and stability facilitate routine QA/QC in battery manufacturing.
• Space-saving design of the GCMS-QP2050 combined with AOC-30i enables compact laboratory layouts.
• SIM and LEI modes allow both sensitive quantification and confident identification of trace impurities.

Future Trends and Possibilities

Advances in mass spectrometer sensitivity and data processing algorithms will enable detection of ever lower impurity levels. Integration with automated sample preparation and real-time monitoring could support inline quality control. Expansion of spectral libraries for novel electrolyte components and degradation products will further streamline impurity identification. Coupling with AI-driven data analysis may accelerate formulation optimization for next-generation batteries.

Conclusion

The Shimadzu GCMS-QP2050 with AOC-30i demonstrated robust performance for simultaneous quantitative and qualitative analysis of carbonate esters, additives, and phosphate ester impurities in lithium-ion battery electrolytes. Excellent calibration linearity, repeatability, and impurity identification capabilities support its use in research and industrial quality control.

References

1. Analysis of Carbonic Esters and Additives in Lithium Ion Battery Electrolytes. Application News No. 01-00708, Shimadzu, 2025.
2. Weber et al., Ion and gas chromatography–mass investigations of organophosphates in lithium ion battery electrolytes by electrochemical aging. Journal of Power Sources, 306 (2016) 193–199.