Analysis of Elemental Impurities in Lithium-Ion Battery Electrolyte Solvents by ICP-MS

Importance of the Topic

Lithium-ion batteries play a central role in consumer electronics, electric vehicles, and stationary energy storage. The purity of electrolyte solvents directly influences battery performance, safety, and longevity. Trace metal contaminants can alter ion mobility, trigger unwanted electrochemical reactions, and accelerate degradation or dendrite growth.

Objectives and Study Overview

This work evaluates a direct analysis method for 21 elemental impurities in typical lithium-ion battery electrolyte solvent blends (DMC/EMC and DMC/EC) using an Agilent 7900 ICP-MS system. The study aims to achieve sub-ppb detection limits, accurate quantification via standard addition, and rapid screening of non-target elements.

Methodology and Instrumentation

An Agilent 7900 ICP-MS equipped with an organic solvent introduction kit, platinum-tipped cones, and an optional fifth gas inlet for O2/Ar was used. Solvent samples were introduced by self-aspiration to avoid peristaltic pump contamination. Carbon matrix interferences were controlled by adding oxygen to decompose carbon, and the ORS4 collision/reaction cell was operated in He collision mode, enhanced He, or H2 reaction mode depending on the element.

Standard addition calibrations (1–500 ppb spikes) were prepared in each solvent mix. A DMC rinse between samples prevented carryover. A six-hour QC sequence with 20 ppb spikes monitored stability. The QuickScan function acquired full-mass spectra in He mode for semiquantitative screening of additional elements.

Key Results and Discussion

Detection limits below 1 ppb were achieved for all target elements in undiluted solvents. Calibration linearity exceeded 0.999 for most analytes. Spike recoveries ranged from 88 to 107 % with precision better than 8 % RSD. QC recoveries over six hours remained within ±20 % of the initial calibration, confirming long-term stability. He-mode QuickScan identified non-target impurities such as Zn, Br, Rh, and Pd, with semiquantitative concentrations consistent with quantitative trends.

Benefits and Practical Applications

• Sub-ppb sensitivity supports stringent quality control in battery materials development.
• Direct analysis of undiluted organic solvents simplifies sample preparation and accelerates throughput.
• Standard addition calibration compensates for complex matrix effects without extensive dilution or derivatization.
• QuickScan screening provides rapid detection of unexpected contaminants.

Future Trends and Opportunities

Advances may include integration of triple-quadrupole (ICP-QQQ) mass filters to further reduce polyatomic interferences, on-line monitoring of solvent purity in production lines, and expansion of screening libraries for novel electrolyte additives. Automation of standard addition workflows and coupling with complementary techniques could enhance throughput and data confidence.

Conclusion

The Agilent 7900 ICP-MS method offers robust, sensitive, and accurate analysis of trace elemental impurities in lithium-ion battery electrolyte solvents. Its high matrix tolerance, low detection limits, and semiquantitative screening capability make it a superior tool for routine QA/QC and research in battery materials.

References

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3. McCurdy E, Kanda T, Yamanaka K, Chen YH, Takahashi J. Enhanced Analysis of Organic Solvents using the Agilent 7700 Series ICP-MS. Agilent Technologies; publication 5990-9407EN.
4. Liu S, et al. Organic matrix effects in inductively coupled plasma mass spectrometry: A tutorial review. Appl Spectrosc Rev. 2022;61(6):461–489.
5. Zou A, Li S, Ang CH, McCurdy E. Direct Analysis of Elemental Impurities in Solvents Used for Lithium-Ion Battery Electrolytes. Agilent Technologies; publication 5994-6227EN.