MCUT Research

Separation and Purification Technology / 2026, vol. 394, 137472

Recyclable deep eutectic solvents support NCA cathodes recycling: green solvent utilization and selective metal recovery

Main authors: Ching-Lung Chen, Shuo-Xuan Zhou, PratimaDevi Sivasubramanian/MCUT

The rapid growth of the electric vehicle industry has led to an increasing accumulation of spent lithium-ion batteries, highlighting the urgent need for sustainable recycling technologies. Conventional hydrometallurgical methods, although effective, rely heavily on strong acids and may cause secondary pollution, necessitating the development of greener alternatives. In this study, a type III deep eutectic solvent (DES), composed of choline chloride and oxalic acid dihydrate, was employed to establish a closed-loop recycling process for ternary NCA (LiNi₀.₈Co₀.₁₅Al₀.₀₅O₂) cathodes.. (論文連結)

In this system, oxalic acid functioned both as a leaching agent and a selective precipitant, enabling the preferential recovery of nickel as nickel oxalate. Under optimal conditions (DES ratio 1:1 M, solid–liquid ratio of 10 g L⁻¹, 110 °C, 8 h), nickel was selectively precipitated as high-purity nickel oxalate, as confirmed by XRD analysis. Meanwhile, efficient leaching of lithium (100%), cobalt (76%), and aluminium (62.5%) was retained in the solution.

Sequential separation was achieved by controlling solution chemistry: cobalt was precipitated as cobalt oxalate through coordination tuning, followed by aluminium recovery as hydroxide via pH adjustment. This stepwise process demonstrates high selectivity and efficiency while reducing environmental impact. Overall, the results highlight the potential of DES-based systems as a sustainable and feasible strategy for lithium-ion battery recycling, contributing to the development of circular economy practices.