Lithium-ion batteries have become increasingly popular due to their high energy density and long lifespan. However, the disposal of these batteries poses environmental challenges. Here is how the use of handheld X-ray fluorescence (XRF) analysis can help in efficient and accurate recycling of lithium-ion batteries.
Lithium-ion batteries are made of multiple components, the most valuable being the cathode that contains between 40 and 70%* of the total value of the battery, depending on its exact chemistry. As of 2023, lithium nickel cobalt manganese oxides (NCM) account for 66% of lithium-ion battery cathode active materials for electric vehicles, followed by lithium iron phosphates (LFP) which account for 24%, and lithium nickel cobalt aluminum oxide (NCA) accounts for the remaining 10%.
How Lithium-Ion Batteries are Recycled
The recycling of lithium-ion batteries involves various methods such as thermal and mechanical treatments, as well as pyrometallurgy or hydrometallurgy processes. The typical scrap metal recycling process includes discharging the batteries and dismantling them to obtain battery cells. The battery cells then undergo shredding and processes to separate the current collectors from the black mass, which contains active materials from the cathode and anode. The black mass can be treated further through hydrometallurgical processes to recover pure salts of lithium, nickel, cobalt, and manganese.
Alternatively, it can be directly smelted using pyrometallurgy to recover cobalt, nickel, and copper in the form of a metal alloy, with lithium transferring to the slag phase. The obtained alloy can be refined into pure salts of base metals using simplified hydrometallurgical processes.
However, it is important to consider that not all recycling methods are economically viable for every type of cathode material.
With the high variability of input material and the use of multiple process steps for the recovery of several valuable commodities, the recycling of lithium-ion batteries is complex. Mostly, the recovered materials need to be analyzed after each major step, either to verify purity or to ensure adequate composition of feedstock for the next step. In addition, companies upstream of the recycling workflow where black mass is recovered need to estimate the market value of the spent battery material shipped to downstream recyclers.
Laboratory analysis of these materials can be time-consuming and expensive to run, with costs sometimes exceeding the value of the analyzed material itself; this creates a need for cost-effective, on-site analysis of recycled materials to enable fast, real-time decisions during the recycling process. There are portable, handheld XRF analyzers, that can identify metal elements right in the scrapyard and have been used for decades.
Analyzing the Elements in Recycled Batteries
Handheld X-ray fluorescence (XRF) analysis is an elemental analysis technique that has proven to be cost-effective in recycling areas such as scrap metal and automotive catalytic converters. The technology helps enable scrap operators to measure elements from magnesium (Mg) to uranium (U) in various types of materials such as metals and alloys. Although handheld XRF does not detect lithium, it can measure most elements from the periodic table including nickel or cobalt.
Handheld XRF is primarily used in the early stages of the battery recycling process. It can identify the type of cathode scrap films, which make up a significant portion of the feedstock. This information is crucial for selecting the appropriate recycling route. While pyrometallurgy is effective for recovering nickel and cobalt from NCM cathode films, it is not suitable for LFP cathode films due to the challenge of recovering lithium.
Handheld XRF is also used to sort battery housings and analyze the resulting products after shredding and separation. It provides information for risk assessment, material treatment, and process efficiency. The valuable black mass can be analyzed for nickel, cobalt, manganese, copper and other elements with minimal sample preparation. Additionally, as noted, handheld XRF can accurately measure those elements in the alloy recovered from smelting.
Is it Worth the Effort?
Because of the variety of technologies and materials used, recycling lithium-ion batteries is a complex journey with multiple possible paths. Handheld XRF helps recyclers by generating lab-quality data in real time, allowing them to optimize their processes and make fast decisions that generate significant benefits. By using this technology, unwanted materials containing heavy metals such as harmful lead or cadmium can be prevented from entering subsequent steps in the recycling workflow. In addition, materials can be accurately sorted and adequate processes for recovery selected depending on the material type (e.g., LFP vs. NCM).
Because handheld XRF can help identify unwanted materials so they can be removed, as well as find the valuable metals, the economic value of incoming and outgoing material can be more accurately estimated, which helps recyclers streamline their operations, and make better decisions more quickly.
More details can be found in the application note: Optimizing lithium-ion battery recycling operations using handheld XRF analysis
Notes and References
- Application note: Optimizing lithium-ion battery recycling operations using handheld XRF analysis
- Portable Scrap Metal Recycling Solutions
- eBook: A practical guide to improving metal and alloy sorting for scrap metal recyclers
*Heiner Heimes et al., Recycling von Lithium-Ionen-Batterien, 2. Edition, Dec 2023, PEM RWTH Aachen University & VDMA, ISBN: 978-3-947920-43-3 and Julia Harty, Six key trends in the battery recycling market, June 2023, Fastmarkets https://www.fastmarkets.com/insights/six-key-trends-battery-recycling-market/
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