Major Component and Elemental Impurity Analysis of Lithium-Ion Cathode Materials Using the ICPE-9820

Importance of the Topic

Accurate determination of both major and trace elements in lithium-ion battery cathode materials is critical for optimizing energy density, ensuring safety, and meeting regulatory standards. High-precision elemental analysis supports quality control in production and improves battery performance and reliability.

Study Objectives and Overview

This work evaluates the performance of the ICPE-9820 inductively coupled plasma atomic emission spectrometer for simultaneous quantification of major components (Li, Co, Ni, Mn) and trace impurities in LiCo0.2Ni0.4Mn0.4O2 cathode materials. The study includes method development, validation (stability, precision, recovery), and comparison with Chinese standard YS/T 798-2012 limits.

Methodology and Instrumentation

Sample Preparation:

• Approximately 0.5 g of cathode powder digested with 2 mL HNO3 and 4 mL HCl by microwave at 230 °C for 15 min.
• Final dilution to 50 mL for stock solution; further dilutions: 10 000× for major component analysis, 1000× for impurity analysis.
• Internal standard Y (1 mg/L) added for major component runs; Li at 70 mg/L matrix matching for impurity standards.

Instrumentation and Conditions:

• Instrument: ICPE-9820 ICP-OES with mini-torch to reduce Ar consumption.
• Nebulizer: 10UES; Chamber: Cyclone HE; Autosampler: AS-10.
• RF Power: 1.20 kW; Plasma gas: 10.0 L/min; Auxiliary gas: 0.60 L/min; Carrier gas: 0.70 L/min.
• Axial view for trace-level sensitivity; radial view for high concentration linearity.

Main Results and Discussion

Major Components:

• Measured concentrations of Li, Co, Ni, Mn matched theoretical values with recoveries of 99–101%.
• Detection limits ~0.02 mg/L; method blanks < detection limit.
• Long-term (2.5 h) and five-day precision RSD < 1% for all elements and Li/(Co+Ni+Mn) ratio.

Impurities:

• Detection limits met YS/T 798-2012 requirements for 20 elements; solid detection limits ranged from 0.00002 to 0.09 mg/kg.
• Spike recoveries between 95% and 106% across all elements.
• Software features (Peak Search, All-wavelength Data Acquisition) enabled selection of interference-free wavelengths (e.g., Zn at 206.200 nm, S at 182.625 nm) without re-measurement.

Benefits and Practical Applications

• Mini-torch design cuts argon usage and lowers operating costs.
• Dual-view optics extend dynamic range, avoiding multiple instruments or sample reruns.
• Post-measurement wavelength addition simplifies method optimization.
• High stability and precision support routine QC in battery material manufacturing.

Future Trends and Opportunities

• Integration with automated sample handling and data analytics for real-time process monitoring.
• Extension of the method to anode materials and electrolytes in lithium-ion and next-generation batteries.
• Development of eco-friendly plasma gases and further reduction of gas consumption.
• Application of machine learning for spectral interference correction and automated wavelength selection.

Conclusion

The ICPE-9820 ICP-OES, equipped with a mini-torch and flexible software tools, provides accurate, precise, and cost-effective analysis of battery cathode materials. Its stable performance and post-measurement flexibility make it ideal for comprehensive elemental analysis in research and quality control environments.

References

• YS/T 798-2012: China National Standard for Lithium Nickel Cobalt Manganese Oxide Cathode Materials.