posted on 2023-04-26, 16:05authored bySalma
H. Alhashim, Sohini Bhattacharyya, Raphael Tromer, Ahmad Kabbani, Ganguli Babu, Eliezer Fernando Oliveira, Douglas S. Galvao, Pulickel M. Ajayan
The
colossal increase in the use of Lithium-ion batteries (LiBs)
necessitates their efficient recycling to ensure a steady supply of
essential cathode materials, e.g., Li, Co, and Ni, as well as to tackle
huge bulks of battery waste. Deep Eutectic Solvents (DESs) are green
solvents with immense potential in the hydrometallurgical recycling
of LiB cathodes, although their leaching mechanism has not been explored.
We investigate the leaching mechanism of the different transition
metals (TM), e.g., Co, Ni, and Li, from the most abundantly used LiB
cathode materials NMC and NCA in an ethylene glycol (EG):choline chloride(ChCl)
based DES. Leaching experiments performed by altering different parameters
and density functional theory (DFT) calculations imply that EG participates
in H-bonding and weakens the metal–oxygen bond of the TMs,
whereas Cl– attacks the metal center to form chlorometalate
complexes. Li on the other hand is surrounded by Cl– ions and leached in the solution. The increased concentration of
ChCl in DES ensures the facile formation of these complexes and enhances
leaching.