Elemental Analysis & Testing in the Lithium-ion Battery Value Chain Using ICP

Growing international interest in electric mobility and energy storage has triggered the need for analytical testing and quality control capabilities within the battery value chain — from the extraction and processing of raw materials, through quality assurance in the production line, to material recovery in recycling, as well as assisting with the research and development of next-generation batteries.

As lithium-ion batteries play an increasingly crucial role in everything from handheld electronics to electric vehicles, analytical laboratories will need to accelerate insights and answers to achieve advancements and meet sustainability goals. Multiple testing methods described in scientific literature and other sources help one to assess battery performance and safety, but do not always provide the most accurate results or optimal analytical workflow.

In this blog post we are going to highlight one important elemental analysis technique that supports battery testing and lab capabilities.

Where is elemental analysis of battery material required?

Elemental analysis of battery materials — including cathode (various types and material composition), anode (mostly high-purity graphite), electrolyte mixture (salts, solvents and additives), and other compounds — is essential to ensure overall quality of production. Today cathode active material (CAM) is, in most cases, by far the most expensive component of batteries and, therefore, requires accurate analysis of its composition. But which elements are usually present in a cathode?

Lithium cells are named after the chemical composition of their cathode material. Typical cathode materials for EV batteries, for instance, are nickel-cobalt-aluminum oxide (Li(NiCoAl)O₂, NCA), nickel-manganese-cobalt oxide (Li(NiMnCo)O₂, NMC), and lithium-iron-phosphate (LiFePO₄, LFP). However, next-generation batteries are in development that may partially replace today’s common battery types in the future.

Verifying the elemental composition of cathode active material is critical to both — the production process and quality control — for finished cathode materials. And, therefore, CAM composition must be measured with extremely high accuracy. Here simultaneous multi-element testing techniques, such as inductively coupled plasma (ICP) technology, enable laboratories and manufacturers to measure the elemental content of raw materials and battery components along the supply chain. To ensure secure and accurate result collection and streamline processes to improve quality, labs can adopt software such as Laboratory Information Management Systems (LIMS)

What is inductively coupled plasma (ICP) technology?

ICP is an analytical technique used to measure and identify elements within a sample matrix based on elements present and detected in an argon (Ar) plasma. ICP analysis requires the use of liquified sample solutions. Therefore, samples are often digested prior to analysis. During analysis Ar carrier gas is used to aerosolize the sample sending droplets through the chamber and into the argon plasma torch. The hot Ar plasma causes the sample to desolvate, atomize and ionize. Subsequently, emitted wavelengths or atomic mass can be detected and quantified.

With ICP technology, most of the elements in the periodic table can be analyzed. The detection can be done either using optical detector based on emitted wavelengths or by using mass spectrometry based on ions and their mass-to-charge ratio. However, detection limit for inductively coupled plasma mass spectrometry (ICP-MS) can extend to parts per trillion (ppt), where the lower limit for inductively coupled plasma optical emission spectrometry (ICP-OES) is parts per billion (ppb).

Discover below several application notes that demonstrate a fast analytical method for determination of major and trace elements in the ternary cathode material of lithium-ion batteries using ICP-OES. The notes describe the method development and present key figures of merit, such as detection limits and stability.

To learn more about ICP fundamentals, discover this education ICP spectrometry webinar series.

Applications for battery material analysis and testing using ICP-OES

Application Note image Application note: Sensitive determination of elements in lithium batteries using the Thermo Scientif…

In lithium-ion batteries proportion and content of the main elements in the ternary cathode material — such as nickel, cobalt and manganese — can affect the performance and cost of the lithium battery significantly, and the content of impurities in the ternary material alters the safety of the battery. Therefore, the accurate determination and quantification of the main elements, as well as trace impurities in the ternary cathode material, becomes particularly important.

In this application note a Thermo Scientific iCAP PRO XP ICP-OES system was used to establish a rapid detection method for determination of major elements and trace impurities in a ternary cathode material used in lithium batteries.

Trace Measure application note image Robust and sensitive measurement of trace element impurities in LiPF6 electrolyte solutions using IC…

The electrolyte plays an important role in the charging and discharging performance of the battery, and hence needs to be checked for potential impurities. The electrolyte is also a sample type that allows the investigation of aging processes, as degradation products from all components of the battery can accumulate within it over time. At the end of its life, all components must be thoroughly screened to ensure that potential environmental contamination and injury risks to personnel disassembling the batteries are minimized.

This study has demonstrated the performance of the Thermo Scientific¢ iCAP PRO XP ICP-OES Duo system for highly sensitive and accurate analysis of impurities in electrolyte solutions containing LiPF6 and organic carbonates, such as ethyl carbonate and ethyl methyl carbonate.

Battery impurities app note image Application note: Determination of elemental impurities in lithium iron phosphate using ICP-OES

Lithium iron phosphate (LFP) has properties that make it an ideal cathode material for lithium-ion batteries. The material is characterized by a large discharge capacity, low toxicity and low cost. But purity of the cathode material is critical and changes in the raw material processing and synthesis can cause the introduction of impurities in the final cathode material. These impurities impact the lifetime and energy storage capacity of the battery, and in extreme cases may affect the integrity of the crystal structure of the battery, causing safety issues.

This application note demonstrates the effective application of the iCAP PRO ICP-OES instrument for analysis of elemental impurities in LFP material. A total of 23 key impurity elements were accurately and sensitively measured.

Composition characterization app note image Application note: Composition characterization of lithium-rich minerals as an exploitable source of …

Lithium used in the production of electric vehicle batteries and other electronic devices is obtained from sources such as underground brines and lithium-rich minerals and rocks. While brine solutions can be potentially rich, relatively easy-to-access sources of lithium, consideration must be given to the potential impact of the exploitation activities themselves on related environmental risks and raw material supply.

The Thermo Scientific¢ iCAP PRO X ICP-OES Duo instrument, equipped with a ceramic D-torch, was used to analyze 12 elements in digested rock samples containing commercially viable amounts of lithium. The results of this study showed that the analysis can be easily performed using a straightforward method to yield high accuracy and excellent analytical robustness.