Graphite recovery from waste Li-ion battery black mass for direct re-use

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Minerals Engineering, Volume 208
Graphite was recovered from two leached (H2SO4 = 2 M, 60 °C, t = 3 h, Fe3+ = 2 g/L) Li-ion battery black mass concentrates with minimized energy consumption. One black mass originated from a mixture of mobile device and power tool batteries, and another from a single electric vehicle battery. The leach residues were pyrolyzed (800 °C, t = 1 h, Ar atmosphere) to remove the polyvinylidene fluoride (PVDF) binder and other non-metallic fractions. The black mass, its leach residue, and pyrolyzed residue were characterized using inductively coupled plasma-optical emission spectrometry (ICP-OES), ion chromatography (IC), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy, and N2 adsorption/desorption. After hydrometallurgical recycling and pyrolysis, the main post-metallurgical black mass impurities were cobalt oxide, iron, acid-resistant boehmite (AlO(OH)), and silicon dioxide. The pyrolysis resulted in electrolyte and binder removal, affected the crystallinity of the remaining boehmite. The recovered graphite-rich residue with impurities identified was tested as an anode in half-cells vs. metal Li. The average specific capacities of recovered graphite-rich residues from both sources were 350 and 250 mAh/g at 0.1C and their capacity retention after 100 cycles was high (80 %) suggesting rather slow deterioration and hence the proposed recycling route being promising for the graphite reuse in new Li-ion batteries.
Funding Information: This research work has been supported by Business Finland BatCircle 2.0 project (Grant Number 44886/31/2020) and the Academy of Finland’s RawMatTERS Finland Infrastructure (RAMI) based at Aalto University. This work was partly funded by the K.H. Renlund Foundation in Finland under the project “Innovative e-waste recycling processes for greener and more efficient recoveries of critical metals and energy” at Åbo Akademi University. This work was supported by the Estonian Research Council (PUTJD1029, PSG926, EAG248). The authors would like to acknowledge X-ray Mineral Services Finland Oy for the conducted elemental mapping, XRD measurements and result interpretation of the black mass samples. Publisher Copyright: © 2024 The Authors
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Chernyaev, A, Kobets, A, Liivand, K, Tesfaye, F, Hannula, P-M, Kallio, T, Hupa, L & Lundström, M 2024, ' Graphite recovery from waste Li-ion battery black mass for direct re-use ', Minerals Engineering, vol. 208, 108587 .