Thoroughly Proven but (as of yet) Uncommon Elemental Analysis Technologies for the Li-ion Battery Supply Chain

The lithium-ion battery supply chain extends from mines and refiners to makers of cells and battery packs to original equipment manufacturers (OEMs).

Determining what elements are present in each material and what amounts can be critical in quality control at various processing phases. Let’s explore two thoroughly proven (but not yet commonly used) analytical technologies for Li-ion battery applications: ED-XRF and ETV-ICP-OES.

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Analyzing graphite

Graphite analysis via ICP-OES

Perhaps the most efficient and reliable method for high-purity graphite analysis combines a proven analytical solution with sample introduction technology that may be unfamiliar to many users in the battery supply chain.

Electro Thermal Vaporization (ETV), a sample introduction technique that can be used with an ICP-OES instrument, has been employed in various applications where difficult-to-digest samples are encountered. Recent advances in methodology and automation have made ETV easier to use and more adapted to higher-productivity applications. One ICP-OES instrument that can handle the application’s analytical requirements is the SPECTRO ARCOS ICP-OES analyzer from SPECTRO Analytical Instruments.

• Compared to ICP-MS instruments, currently the most popular technique for graphite analysis, ETV-ICP-OES technology is faster and simpler; it also costs the same or less to purchase and less to operate.
• While compared to XRF analysis, ICP-OES/ ETV is destructive (consuming the impurities in the sample in the high-temperature plasma), it demonstrates exceptionally high sensitivity (and thus low LODs) that is superior by three orders of magnitude — ppb for the ICP results, versus only ppm for an XRF analyzer. For high-purity graphite analysis, ICP-OES/ETV is the better choice.

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Analyzing lithium salts and cathode materials

Salt and cathode material analysis via ICP-OES

The industry standard for these applications is ICP-OES analysis. In cathode materials, the composition of the main elements, lithium, and depending on the type, additional main elements like Co, Fe, Mn, Ni, P, and Ti must be determined with extremely high precision and accuracy. Likewise, impurities of less than 10 ppm need to be determined for most elements.

ICP-OES delivers good results for the analyses necessary for cathode and electrolyte materials. Analyzers may exhibit essential differences in factors such as sensitivity, precision, speed of analysis, ease of use, and cost of ownership. However, a well-designed ICP-OES analyzer can analyze the materials’ main components with high precision and can identify metal impurities at the required ppm levels for ensured quality control during processing.

Traditionally, radial observation delivers higher precision, while axial observation offers higher sensitivity. To cater for these requirements, the SPECTRO ARCOS — the flagship ICP-OES instrument from SPECTRO Analytical Instruments — is available as a MultiView Model, offering axial and radial observation in a single instrument. With the inclusion of the DSOI technology the sensitivity of the radial observation is up to a factor 2 improved, now. This means, the sensitivity of the SPECTRO ARCOS analyzer’s radial model is sufficiently high and can produce good results for trace element analysis in cathode material and lithium salts as well as high precision for the determination of main components in cathode materials. Users can choose a radial model for their complete battery material analysis work — thus avoiding additional analysis using the axial plasma observation technique.

Since the material can be rather line rich, the high resolution the SPECTRO ARCOS provides over a wide wavelength range combined with advanced background correction techniques like smart background correction (SBC) improves the performance, particularly the accuracy at low concentration levels.

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Cathode and lithium salt analysis via XRF

Where precise lithium concentrations need to be determined, XRF analyzers fall short. However, for certain other battery processing work, XRF outdoes ICP-OES in speed, simplicity, and ease of operation — often calling for little or no sample preparation. And, in many cases, it’s significantly less expensive than ICP-MS or ICP-OES technologies.

XRF is best applied for fast screening tasks. For example, it can quickly distinguish between lithium iron phosphate (LiFePO4) and lithium manganese oxide (LiMn2O4). In the popular cathode material lithium nickel manganese cobalt (NMC 811), the 8:1:1 ratio between nickel, manganese, and cobalt is critical. A well-calibrated XRF analyzer can swiftly determine the stoichiometry of a given sample and confirm that this ratio holds.

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The analyzers

Precise analytical solutions are required to ensure material quality (and ultimately battery performance) at several steps in the lithium-ion battery supply chain. However, many analyzer suppliers offer suitable instruments for only one or two battery applications.

By contrast, SPECTRO Analytical Instruments has solutions across the supply chain. Ideal performers for the battery world include its SPECTRO ARCOS and SPECTRO XEPOS analyzers.

• The SPECTRO ARCOS ICP-OES analyzer is ideal for the most demanding elemental analyses in battery-related industry and research. Leading the SPECTRO ICP-OES line, it offers numerous technological and user-centric advantages.
• The SPECTRO XEPOS energy dispersive X-ray fluorescence (ED-XRF) spectrometer redefines its category with exceptionally improved performance levels. For cathode and lithium salt manufacturing applications that demand fast, easy, simple, ultra-affordable screening for elemental concentrations and stoichiometry, SPECTRO XEPOS is an excellent choice.

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For a more in-depth discussion, with detailed sample analysis data, of the advantages of using ETV-ICP-OES and XRF for element analysis in the lithium-ion battery supply chain — plus comparisons to traditional analytical technologies — get the white paper, “Recent Advances in Elemental Analysis for the Lithium-Ion Battery Supply Chain.”

Download it now — no registration is necessary!

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