The need to monitor the release of ultrafine particles and airborne carbon nanotubes during mechanical recycling of lithium-ion batteries

Despite the growing demand for battery gigafactories and recycling plants, there is a paucity of research on the release of airborne nanomaterials during the mechanical processing and recycling of lithium-ion batteries (LIBs). Therefore, the potential release of ultrafine particles (UFPs) and carbon nanotubes (CNTs) was investigated to demonstrate an appropriate aerosol measurement strategy for occupational health monitoring. UFP size distributions were characterized during the shredding (<1 mm) and milling (<0.5mm) operations using an optical particle sizer (OPS) and a scanning mobility particle sizer (SMPS). Concurrently, a Raman spectroscopy-based method enabled to selectively quantify airborne CNT mass and differentiate between multi and single wall forms (MWCNTs/SWCNTs). Method validation demonstrated consistent sampler performance with limits of quantification of 0.013 ng for SWCNTs and 0.27 ng for MWCNTs. The high chemical specificity of the Raman spectroscopy, enabling clear distinction between different carbon allotropes and resulting in minimal quantification bias, even in the presence of complex carbonaceous matrices. Overall, the proposed tried approach is robust, selective and valid for the monitoring of nanomaterial exposure in battery manufacturing and recycling environments.