Determination of Multiple Elements in Lithium Salts using Autodilution with ICP-OES

Importance of the Topic

The sustained growth of electric vehicles and renewable energy storage has escalated the need for high-purity lithium salts, such as lithium chloride, carbonate and hydroxide. Impurities in these precursor chemicals can impair battery performance and reduce cycle life. Rapid, reliable multi-element analysis ensures quality control at every stage of lithium-ion battery precursor production.

Objectives and Study Overview

This study evaluates an automated workflow for quantifying 28 trace elements plus lithium in technical-grade lithium chloride (LiCl). Using an Agilent 5800 Vertical Dual View ICP-OES equipped with an ADS 2 autodilutor and SPS 4 autosampler, the goal was to demonstrate fast calibration, dilution and analysis with minimal human intervention and high accuracy across a broad concentration range.

Used Instrumentation

• Agilent 5800 VDV ICP-OES with vertical plasma, SSRF power source and Cooled Cone Interface for enhanced matrix tolerance
• Integrated Advanced Switching Valve (AVS 7)
• Agilent ADS 2 Advanced Dilution System for autocalibration, prescriptive and reactive dilutions
• Agilent SPS 4 autosampler for automated sample delivery
• SeaSpray nebulizer, cyclonic spray chamber and 1.8 mm semi-demountable VDV torch
• ICP Expert Pro software for full method control and summary-row data selection

Methodology and Sample Preparation

LiCl solid was dissolved to prepare a 1% w/v solution in 10% HNO₃ following national standard GB/T 11064.16-2013. A single stock solution containing 1 mg/L of 27 elements and 10 mg/L Li was automatically diluted by ADS 2 to generate five-point calibration curves (0–1 mg/L for trace elements; 0–10 mg/L for Li). Reactive dilution automatically adjusted over-range samples or out-of-range internal standards, while prescriptive dilution applied defined factors (up to 400×) on demand. Quality control used a 10% HNO₃ blank (CCB) and a 5 mg/L (0.5 mg/L Li) verification standard (CCV), with yttrium, rubidium, tellurium, bismuth and indium as internal standards.

Main Results and Discussion

All 28 elements exhibited linear calibration (R² ≥ 0.99986). Method detection limits were below 1 mg/kg for most analytes. Spike recoveries at 0.1 and 0.25 mg/L fell within 90–110%. A 10-hour continuous run with 375 measurements showed QC recoveries within 100 ± 10% and precision (RSD) < 3%. Autocalibration reduced standard preparation time from over one hour to under 20 minutes.

Benefits and Practical Applications

• Automated calibration and dilution minimize manual errors and chemical waste
• Single-vial analysis of major (Li) and trace elements simplifies workflow
• Reactive dilution ensures data integrity by re-measuring over-range samples
• High throughput supports routine QC of battery precursor materials

Future Trends and Applications

Advances in autodilution and software-driven analysis will further streamline routine quality control in battery materials, pharmaceuticals and environmental monitoring. Integration with cloud-based data management and predictive maintenance could enhance traceability, reduce downtime and support scalable manufacturing.

Conclusion

The Agilent 5800 VDV ICP-OES combined with ADS 2 and SPS 4 offers a fully automated, robust solution for multi-element determination in high-matrix lithium chloride. The system delivers rapid calibration, precise dilution, excellent accuracy and long-term stability, enabling reliable QC of LIB precursor chemicals with reduced labor and consumable costs.

References

• Pan X.; Dou Z.; Zhang T.; Meng D.; Han X. Basic Study on Direct Preparation of Lithium Carbonate Powders by Membrane Electrolysis. Hydrometallurgy 2020, 191, 105193.
• Purification of Industrial Grade Lithium Chloride for the Recovery of High Purity Battery Grade Lithium Carbonate. Sep. Purif. Technol. 2019, 214, 168–173.
• A Practical Guide To Elemental Analysis of Lithium Ion Battery Materials Using ICP-OES. Agilent Technologies, 5994-5489EN.
• Agilent Advanced Dilution System (ADS 2) – Technical overview. Agilent Technologies, 5994-7211EN.
• GB/T 11064.16-2013. Methods for Chemical Analysis of Lithium Carbonate, Lithium Hydroxide Monohydrate, and Lithium Chloride. National Standard of China, 2013.