Donatella Aiello, Carmen Lo Sardo, Rosangela Elliani, Antonio Tagarelli, Anna Napoli

Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende, 87036, Cosenza, Italy.

The consumption of critical metals, such as Li and Co, is increasing due to the high production of electronic equipment that employ energy storage devices. This also increases the accumulation of spent batteries, which are harmful to the environment. Recycling spent lithium-ion batteries (LIBs) and recovery their constituent elements is crucial to meet the demand and supply chain for the valuable metals [1]. Current techniques for recycling LIBs are based on methods that can cause serious environmental damage so new, simpler, and more sustainable methods are needed [2]. The aim of this research project is to develop an eco-friendly analytical approach for the recovery of valuable metals from spent batteries. 

The proposed method consists in the extraction of metals from the black mass (BM), a black powder obtained by grinding whole spent batteries and containing all their components: metals, graphite and organic polymers. Leaching was performed by testing three different extracting mixtures at room temperature and pressure and under controlled time conditions to assess the extraction efficiencies. An organic three-solvent system was used for metal leaching under strong, mild and mild/mixed conditions. The experimental protocols were combined with instrumental analysis, such as LDI-MS, to establish the presence of PVDF polymer, and ICP-MS, to assay metal cations in the BM residue and in the cation-enriched solution. The results showed that these methods ensure high recovery rates of the metal cations Ni, Co, Li, Mn, Cu, Al, Fe, Zn and Mg. Leaching using the extracting mixture in strong conditions provided an extraction efficiency, after 168 hours of reaction, greater than 90% for all the metals except Mg. The mild system, instead, resulted in only copper and iron achieving extraction efficiencies above 80%, while the other metals remained below 50%.

Extraction with the mild/mixed solvent system produced metal concentrations in solution, after 96 hours, ten times higher than those obtained under mild conditions for some metals, such as Co and Li. Improvements in the leaching time and ratios of the solvents involved in the mild/mixed system may lead to results comparable to those obtained under strong conditions to develop an eco-friendly and efficient method for the recovery of metals from spent LIBs.miche, Università della Calabria, Arcavacata di Rende, 87036, Cosenza, Italy.

Acknowledgments: this work was financially supported by the Research Program “Tech4You-Technologies for climate change adaptation and quality of life improvement”, Project Code ECS 00000009, CUP H23C22000370006, founded by PNRR

Keywords: lithium-ion batteries, battery recycling, metals recovery

References

1. Mishra G., Jha R., et al., Journal of Environmental Chemical Engineering, 10 (2022), 108534. DOI: 10.1016/j.jece.2022.108534.

2. Jang Y., Hou C., et al, Chemosphere, 317 (2023), 137865. DOI: 10.1016/j.chemosphere.2023.137865.