Exploring Trace Elemental Analysis in Lithium-Ion Battery Materials

Spectroscopic techniques are essential for the advancement, production, and sustainable disposal of lithium-ion batteries. The ongoing research in this space highlights the use of atomic spectroscopy, such as inductively coupled plasma–mass spectrometry (ICP-MS) and inductively coupled plasma–optical emission spectroscopy (ICP-OES), to ensure elemental purity and precise material ratios during manufacturing and recycling. In addition, molecular methods like Raman and Fourier transform infrared (FT-IR) spectroscopy are utilized to monitor chemical changes and structural stability within battery cells in real time.

In this Q&A overview, we illustrate how modern spectroscopy is enabling the global transition to electric mobility and renewable energy.

Why is trace element analysis considered the cornerstone of lithium-ion battery (LIB) safety and performance?

Trace element analysis is critical because the chemical purity of battery materials directly dictates their safety, longevity, and efficiency.^1,2 As production scales from laboratory research to massive gigafactories, managing cell-to-cell variability becomes a significant challenge.² Even part-per-million (ppm) levels of magnetic metal contaminants such as iron (Fe), nickel (Ni), chromium (Cr), or zinc (Zn) in cathode powders can cause internal short circuits, potentially leading to thermal runaway.^2,3 Furthermore, the industry is seeing a shift in purity demands from the conventional 99.5% metals-basis purity to 99.9%, with expectations to reach 99.999% for specific next-generation applications.² By conducting elemental analysis, manufacturers make sure that raw materials, intermediates, and final products meet these rigorous specifications.²

What are the primary spectroscopic "workhorses" used for elemental analysis in the battery value chain?

For elemental analysis, atomic spectroscopy techniques, such as ICP-OES and ICP-MS, are routinely used. Each technique has different strengths, so they are used in different applications in the battery value chain. For example, ICP-OES is favored for its robust plasma, wide dynamic range, and ability to analyze complex matrices with high total dissolved solids (TDS), making it ideal for checking major elemental ratios in cathodes and electrolytes.^1,4,5 In contrast, ICP-MS offers higher sensitivity, allowing for the quantification of ultra-trace impurities at the part-per-billion (ppb) level, which is essential for certifying the high-purity battery-grade feedstocks required for advanced lithium-ion battery manufacturing.^1–3 Additionally, laser-induced breakdown spectroscopy (LIBS) and micro-discharge optical emission spectroscopy (µDOES) are emerging as vital tools for in-line process monitoring, providing real-time data on electrode composition during the manufacturing process.^1,3

How does ICP-OES specifically improve the production of cathode materials like nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP)?

The performance of LIBs is heavily influenced by the precise stoichiometry of the cathode.⁵ For instance, in lithium nickel manganese cobalt oxide (NMC) cathodes, the molar ratios of Ni:Mn:Co must be accurately controlled to balance energy density and stability.⁵ High-precision ICP-OES utilizes manual integration to measure internal standards and analytes simultaneously, achieving an exceptional relative standard deviation (RSD) of 0.2% or less.⁵ This level of precision allows manufacturers to confirm that material batches are consistent over time, with stability tests showing that molar ratios remain steady within 0.3% over repeated measurements.⁵ Similarly, for lithium iron phosphate (LFP) cathodes, ICP-OES ensures the concentration of Li, Fe, and P is stable, which is vital for maintaining the battery's operational characteristics.⁵

What unique analytical challenges do raw materials like lithium brines and electrolytes present?

Raw material analysis is complicated by extreme matrices. Underground brine repositories, a major source of lithium, contain very high levels of sodium chloride, which can clog conventional nebulizers and torch injectors.⁴ Analysts must use specialized sample introduction systems, such as ceramic torches and sheath gas adaptors, to prevent "salting up" during long analytical runs.⁴ On the other hand, electrolytes, typically lithium hexafluorophosphate (LiPF₆) dissolved in organic carbonates, contain high organic solvent loads and can partially hydrolyze to form hydrofluoric acid (HF).⁴ This necessitates the use of HF-resistant components made from materials like PTFE or alumina rather than standard quartz, which would easily be corroded by the acid.^4,5

How do spectroscopic techniques help researchers understand and prevent battery aging and degradation?

Battery aging and degradation is often driven by side reactions at the electrode-electrolyte interface.¹ Elemental analysis tracks transition metal dissolution (TMD), where metals like manganese leach from the cathode into the electrolyte and migrate to the anode, disrupting the solid electrolyte interphase (SEI).² Techniques like X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy are used to characterize the SEI layer, identifying the chemical species formed and monitoring how they evolve during cycling.^1,3 Furthermore, analyzing the soot and gas produced during thermal runaway using gas chromatography–mass spectrometry (GC-MS) and FT-IR helps researchers understand degradation pathways and optimize additives to enhance safety.^1,2

What is the role of trace element analysis in the growing battery recycling industry?

Recycling is essential for a sustainable supply chain, as it recovers valuable elements like lithium, cobalt, and nickel from spent batteries.^3,5 The recycling process often results in "black mass,” which is a complex, difficult-to-digest mixture of carbon, graphite, residual electrolyte, and various metals.⁵ ICP-OES is used to perform semi-quantitative screenings of this black mass to identify all present elements, followed by a quantitative analysis to determine the exact number of recoverable metals.⁵ Once these materials are leached and purified, ICP-MS is employed to certify that the regenerated precursors meet the stringent ppb-level purity specifications required for re-entry into the manufacturing stream, ensuring that recycled batteries perform as well as those made from virgin materials.³

How is the integration of artificial intelligence (AI) and machine learning (ML) changing battery analysis?

Currently, spectroscopy is undergoing massive changes thanks to the emergence of artificial intelligence (AI) and machine learning (ML) being integrated in normal workflows. Using AI and ML suggests that the field is moving toward real-time, data-driven diagnostics.³ Large spectroscopic data sets, including electrochemical impedance spectroscopy (EIS), Raman, and near-infrared (NIR) spectra, are being processed through ML algorithms to predict a battery's lifespan.³ For example, variational autoencoders can identify specific degradation modes, such as lithium plating, from impedance spectra without requiring expert human interpretation.³ This integration supports process analytical technology (PAT) in factories, where AI models interpret spectral data in milliseconds to catch defects instantly on the production line.³

References

1. Workman, Jr., J. A Comprehensive Review of Spectroscopic Techniques for Lithium-Ion Battery Analysis. Spectrosc. Suppl. 2024, 39 (s11), 6–16. DOI: 10.56530/spectroscopy.ii3689u3
2. Kroukamp, E.; Metzger, M.; Hobold, G. M.; Baumann, S.; Rivera, C. From Bench to Factory: The Role of Chemical Purity and Process Control in Lithium-Ion Battery Innovation. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/from-bench-to-factory-the-role-of-chemical-purity-and-process-control-in-lithium-ion-battery-innovation (accessed June 26, 2026).
3. Workman, Jr., J.; Wetzel, W. Lithium-Ion Battery Analysis: Four Years of Spectroscopic Advances in Research, Manufacturing, and Quality Assessment. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/lithium-ion-battery-analysis-four-years-of-spectroscopic-advances-in-research-manufacturing-and-quality-assessment (accessed June 26, 2026).
4. Sengupta, S.; Surekar, B.; Kutscher, D.; Nelms, S. Analysis of Trace Elements as Impurities in Materials Used for Lithium-Ion Battery Production. Spectrosc. Suppl. 2022, 37 (s9), 6–12. DOI: 10.56530/spectroscopy.yc5673v9
5. Neubauer, K. Using ICP-OES to Improve Lithium-Ion Battery Performance and Reduce Waste. Spectrosc. Suppl. 2023, 38 (s9), 6–11. DOI: 10.56530/spectroscopy.vz5170I2