From the Experts: Creating an XRF calibration kit for battery materials

von Umesh Tiwari, Monday, 21st October 2024

As the world transitions toward more sustainable energy, the need for batteries as storage devices has risen exponentially. As a result, battery materials are getting more expensive, leading to a greater focus on increasing the efficiency of battery production processes. In this context, X-ray fluorescence (XRF) has become a staple in battery elemental analysis.

Calibrating XRF instruments is a common method for improving their capabilities. Yet, until now there have been no commercially available certified reference materials (CRMs) for battery-specific XRF calibration. We met with our XRF Application Specialist Florine Aalders to learn more about Malvern Panalytical’s solution – the newly developed XRF calibration kit for battery materials.

The need for calibration materials

The development of this solution began with the needs shared by our customers in the battery industry. “Several customers sought a solution that would help optimize and monitor their production process”, Florine says. “Indeed, improving process efficiency is critical as the industry has become increasingly competitive. More accurate and precise elemental analysis is a key part of the solution – but further increasing the quality of XRF analysis was not possible until now”.

Why? Florine explains: “XRF is a comparative method, so to screen the material composition of samples in the most accurate way possible, you need reference materials that the instrument can use to compare against what it finds in the sample. However, commercial reference materials for battery materials including nickel, manganese, and cobalt did not exist, nor did our customers have the capabilities to produce them.”

Meet Florine and learn more about Malvern Panalytical’s XRF calibration kit for battery material analysis.

How XRF calibration works

To understand how to calibrate an XRF spectrometer, we must first know how XRF works. It starts by projecting X-rays onto a sample: when these X-rays strike the atoms in the sample, a fluorescent ‘fingerprint’ is produced. Each element leaves a trace specific to itself in this fingerprint, and the intensity of this signal depends on the concentration of each element present. By comparing these fingerprints to those of multiple standards, an XRF instrument can quickly and reliably determine not only which elements are present in a sample, but in what proportions, to a relative accuracy of about 0.1 to 0.3%.

Malvern Panalytical’s Zetium XRF can analyze elemental composition in two ways. The first method is the standardless screening of input materials, called Omnian, which detects and semiquantitatively estimates elemental composition. However, this doesn’t provide the accuracy needed for battery processes such as cathode material production and quality control. The second method must be used, which involves calibration using CRMs.

Florine explains: “Calibration is similar to how a vaccine exposes the body to a controlled amount of a virus to help the body find and fight it”. Calibration thus allows an XRF instrument to more accurately and precisely identify the presence and rate of specific elements in a sample.

A dedicated XRF calibration kit for batteries

“Responding to customer needs, we developed the first calibration kit with a dedicated set of CRMs for nickel, manganese, and cobalt oxides (NMC), which can be extended with elemental oxides like aluminum, calcium, zirconium, sodium, and sulfur”, says Florine. The kit includes detailed instructions and training for sample preparation and calibration, 12 synthetic mixtures specifically designed for the preparation of XRF fused bead samples, a fusion recipe, and an XRF application method template.

Equipped with the Malvern Panalytical XRF calibration kit, an Eagon2^® fusion machine, and a Zetium XRF spectrometer, manufacturers can thus obtain highly accurate and precise elemental analysis results for their NMC batteries. The package is also suitable for other cathode chemistries such as lithium nickel cobalt aluminum oxide, lithium cobalt oxide, lithium manganese oxide, and their precursors.

“With this kit, customers can optimize their battery production process daily”, Florine concludes. “It’s a flexible solution that helps maintain the highest quality for battery materials.”

Find out more about the kit on our website – and if you’d like a more personalized discussion, feel free to contact Florine at florine.aalders@malvernpanalytical.com.

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