Investigation of the Storage Behavior of Shredded Lithium‐Ion Batteries from Electric Vehicles for Recycling Purposes

Abstract

Shredding of the cells is often the first step in lithium-ion battery (LIB) recycling. Thus, LiNi1/3 Mn1/3 Co1/3 O2 (NMC)/graphite lithium-ion cells from a field-tested electric vehicle were shredded and transferred to tinplate or plastic storage containers. The formation of hazardous compounds within, and being released from, these containers was monitored over 20 months. The tinplate cans underwent fast corrosion as a result of either residual charge in the active battery material, which could not fully be discharged because of contact loss to the current collector, or redox reactions between the tinplate surface and metal parts of the shredded material. The headspace compositions of the containers were investigated at room temperature and 150 °C using headspace-gas chromatography-mass spectrometry (HS-GC-MS). Samples of the waste material were also collected using microwave-assisted extraction and the extracts were analyzed over a period of 20 months using ion chromatography-electrospray ionization-mass spectrometry (IC-ESI-MS). LiPF6 was identified as a conducting salt, whereas dimethyl carbonate, ethyl methyl carbonate, and ethylene carbonate were the main solvent components. Cyclohexylbenzene was also detected, which is an additive for overcharge protection. Diethyl carbonate, fluoride, difluorophosphate and several ionic and non-ionic alkyl (fluoro)phosphates were also identified. Importantly, dimethyl fluorophosphate (DMFP) and diethyl fluorophosphate (DEFP) were quantified using HS-GC-MS through the use of an internal standard. DMFP, DEFP, and related compounds are known as chemical warfare agents, and the presence of these materials is of great interest. In the case of this study, these hazardous materials are present but in manageable low concentrations. Nonetheless, the presence of such compounds and their potential release during an accident that may occur during shredding or recycling of large amounts of LIB waste should be considered.

Chromatographic Techniques in the Research Area of Lithium Ion Batteries: Current State-of-the-Art

“…The relative quantities of decomposition products in relation to their storage time (in shredded state) was examined by Grützke and coworkers [210]. Positive and negative chemical ionization was used to precisely describe a large variety of different decomposition products including phosphorous and oligocarbonate compounds.…”

The Role of Sub- and Supercritical CO2 as “Processing Solvent” for the Recycling and Sample Preparation of Lithium Ion Battery Electrolytes

“…Besides the dangers regarding working safety when handling spent lithium ion batteries or shredded recycling waste, the fluorinated compounds and hydrofluoric acid can interfere or damage industrial scaled recycling processes and therefore have to be removed before the recycling process by extraction [ 104 ]. For post-mortem analysis and aging analysis of LIB electrolytes, extraction is inevitable, as well.…”

Qualitative and quantitative investigation of organophosphates in an electrochemically and thermally treated lithium hexafluorophosphate-based lithium ion battery electrolyte by a developed liquid chromatography-tandem quadrupole mass spectrometry method

“…14 These compounds are nerve agents, whose toxic effect bases on the irreversible reaction with a mammal enzyme acetylcholinesterase. 15 Furthermore, these compounds were recently found in material from a lithium ion battery recycling process using GC-MS. 16 With regard to the increasing demand on LIB working at high potentials, investigations regarding the quantication of any decomposition products should be performed.…”

“…The concentration was determined by GC-MS and only for DMFP and DEFP with limits of detection (LOD) in the low ppm range for both compounds. 16,20 The study of trialkyl phosphates, as further degradation products, was not performed due to their low contents. The LC-MS/MS technique working in a multiple reaction monitoring scan (MRM) mode is more specic as total ion current (TIC) or selective ion monitoring (SIM) modes of GC-MS.…”