Analysis of Carbonic Esters and Additives in Lithium Ion Battery Electrolytes

Importance of the Topic

Lithium ion batteries power electric vehicles and grid storage applications. Quality and performance of these batteries depend heavily on the composition and purity of carbonic esters and functional additives in the electrolyte. Accurate, fast, and reproducible analysis of these components is essential for routine quality control, scale-up of production, and development of new formulations.

Study Objectives and Overview

This work demonstrates the use of the Shimadzu Brevis GC-2050 gas chromatograph with flame ionization detection (FID) and nitrogen carrier gas to separate and quantify eight typical electrolyte components. The study covers mixed standards and real commercial electrolyte samples to assess separation, linearity, repeatability, and quantitative performance under space-constrained laboratory conditions.

Applied Methodology

Mixed standard solutions of eight compounds (dimethyl carbonate, ethyl methyl carbonate, vinylene carbonate, diethyl carbonate, fluoroethylene carbonate, ethylene carbonate, propylene carbonate, and 1,3-propanesultone) were prepared in dichloromethane at six concentration levels (10–500 mg/L). Calibration curves were constructed from five replicate measurements per level. Commercial electrolyte samples were diluted 1 000-fold in dichloromethane under inert conditions to prevent precipitation and moisture‐induced reactions.

Used Instrumentation

• Gas chromatograph: Shimadzu Brevis GC-2050
• Detector: Flame ionization detector (FID) at 250 °C
• Column: SH-I-5MS (30 m × 0.25 mm i.d., 0.25 µm film)
• Carrier gas: N₂ at constant linear velocity (25 cm/s)
• Injector: Split mode (30:1) at 250 °C
• Oven program: 40 °C (3 min) → 10 °C/min → 160 °C (5 min)
• Makeup gas: N₂ (24 mL/min), H₂ (32 mL/min), air (200 mL/min)

Main Results and Discussion

All eight compounds were baseline resolved within 20 minutes. Calibration curves exhibited excellent linearity (R² ≥ 0.999), and peak area repeatability across five injections showed relative standard deviations between 0.8 % and 1.7 %. Analysis of four commercial electrolyte formulations revealed distinct profiles of carbonates consistent with supplier specifications. Quantitative results ranged from ~278 to 302 mg/mL for dimethyl carbonate and ~398 to 415 mg/mL for ethylene carbonate, demonstrating the method’s accuracy and applicability to real samples.

Benefits and Practical Applications

• High separation efficiency and reproducibility support routine QC workflows.
• Use of nitrogen carrier gas reduces operating costs and reliance on helium.
• Compact instrument design optimizes limited laboratory space.
• Fast analysis cycle enables high throughput of battery electrolyte samples.

Future Trends and Potential Applications

Integration of automated sample preparation and coupling with mass spectrometry could expand detection to trace additives and degradation products. Adapting micro‐bore columns and faster temperature ramps may further increase throughput. The method may be extended to next-generation battery chemistries and environmentally friendly solvent systems.

Conclusion

The Shimadzu Brevis GC-2050 with FID and nitrogen carrier gas offers an efficient, reliable solution for quantitative analysis of carbonic esters and additives in lithium ion battery electrolytes. Excellent separation, strong linearity, and low variability confirm its suitability for routine quality control and research applications.