Determination of Elements in a Solid Sulfide Electrolyte using ICP-OES

Significance of the Topic

The demand for high performance energy storage drives the development of solid-state lithium-ion batteries. Inorganic superionic conductors like Li10GeP2S12 offer higher ionic conductivity, improved safety, and thermal stability compared to liquid electrolytes. Ensuring the purity of these solid electrolytes is critical because trace elemental contaminants can disrupt crystal lattices, shorten battery life, and pose safety risks.

Objectives and Study Overview

This study developed and validated a robust ICP-OES method using the Agilent 5800 VDV to quantify 29 elements in battery-grade Li10GeP2S12. Key goals included establishing accurate calibration, assessing detection limits, verifying precision and accuracy through spike recovery, and demonstrating long-term analytical stability.

Methodology

Ultrafine LGPS powder was digested by microwave heating in reverse aqua regia (3 mL HCl, 9 mL HNO3, 1 mL water) to handle high sulfide content. Digested solutions were diluted to 50 mL, yielding 0.2% matrix in 24% reverse aqua regia. Calibration standards (0.050–0.500 mg/L) and internal standards (Y and Rb) were prepared in matching matrix. Spike samples at 0.200 mg/L were used to evaluate method accuracy.

Used Instrumentation

• Agilent 5800 Vertical Dual View ICP-OES with SPS 4 autosampler and ICP Expert software Pro-pack
• SeaSpray nebulizer, cyclonic spray chamber, demountable VDV torch
• IntelliQuant Screening, Intelligent Rinse, Early Maintenance Feedback features

Main Results and Discussion

Calibration curves for all 29 elements exhibited excellent linearity (R² 0.999–1.000). Detection limits ranged from 0.015 to 4.84 µg/L in solution (0.0075–61.9 mg/kg in sample). Spike recoveries for trace elements fell within 94–100%, and major elements (Li, Ge, P, S) agreed within 100±20%. Over 241 measurements in an 8-hour sequence, QC recoveries remained within 100±5% with RSDs <2.5%, confirming method robustness. Intelligent Rinse reduced rinse times adaptively, saving over 60 minutes per 100 samples. Early Maintenance Feedback ensured consistent performance, minimizing downtime.

Advantages and Practical Applications

• Rapid, simultaneous multi-element analysis in complex sulfide matrices
• High sensitivity and tolerance to dissolved solids for battery materials
• Efficient method development via IntelliQuant Screening
• Time savings through adaptive rinsing and automated maintenance alerts

Future Trends and Opportunities

Integration of solid-state electrolyte analysis into high-throughput workflows will accelerate battery material screening. Advances in software automation and machine learning for spectral deconvolution may further enhance accuracy. Expanding this ICP-OES approach to emerging electrolyte chemistries and real-time inline quality control could support next-generation energy storage development.

Conclusion

The validated Agilent 5800 VDV ICP-OES method delivers reliable quantification of 29 elements in Li10GeP2S12, combining high throughput, low detection limits, and robust maintenance features. This approach supports rigorous quality control for solid-state battery electrolytes, ensuring material purity and performance consistency.

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