Design of Recycling Processes for NCA-Type Li-Ion Batteries from Electric Vehicles toward the Circular Economy

Abstract

NCA batteries represent 8% of the market share, and the literature lacks recycling studies and routes toward a cost-effective recycling process. The present study aimed to develop the hydrometallurgical recycling process of NCA cylindrical batteries. The cells were discharged, followed by physical treatment before leaching. Three different acids were evaluated: H2SO4, H3PO4, and citric acid. Reducing agents were not necessary due to the presence of Al foils, which reduces leaching costs. Citric acid represented a better cost-effective option, but solid–liquid separation represents a drawback to the process. After H2SO4 leaching at 90 °C for 90 min in a solid–liquid ratio of 1/5 and 2.0 mol/L without Cu leaching, Al was separated by precipitation followed by solvent extraction for Co separation using Cyanex 272. Ni was obtained as hydroxide, and Li crystallized as sulfate. The mass balance demonstrated that about 92% of Li, 80% of Ni, and 85% of Co can be recovered in hydrometallurgical processing. Products with purity >95% can be used in battery and stainless-steel production. The process has the potential to have a low CO2 footprint, and future studies will explore it.

Efficient Leaching of Metal Ions from Spent Li-Ion Battery Combined Electrode Coatings Using Hydroxy Acid Mixtures and Regeneration of Lithium Nickel Manganese Cobalt Oxide

“…In the lithium cobalt oxide example, Martins and co-workers have reported quantitative leachings of both Li and Co from LiCoO 2 battery material by using 1.0 M aqueous citric acid without any additional reagents [31]. Similarly, de Castro and co-workers used an aqueous solution of citric acid without other reagents and reported over 80% leaching for Li, Ni, and Co at 90 • C [32].…”

“…Then, the cathode material was regenerated by the addition of lithium acetate, precipitation as oxalate by the addition of oxalic acid, followed by pyrolysis at 900 • C [23]. The use of common hydroxy polycarboxylic acid (citric acid) without an oxidizing agent for leaching metals from simpler mixed metal oxides such as lithium cobalt oxide and lithium nickel cobalt oxide is known [31,32]. In the lithium cobalt oxide example, Martins and co-workers have reported quantitative leachings of both Li and Co from LiCoO 2 battery material by using 1.0 M aqueous citric acid without any additional reagents [31].…”