A Dual Closed‐Loop Process to Recycle High Nickel Cathode of Spent Lithium‐Ion Batteries via Deep Eutectic Solvents: Computational Screening and Experimental Validation

Abstract

ABSTRACT Deep eutectic solvents (DESs) have displayed a significant potential in green recycling of spent lithium‐ion batteries (LIBs) cathode materials. In this study, we proposed a computational screening strategy based on the binding energy and hydrogen bonding performance via density functional theory and molecular dynamic calculation, achieving a novel DES system composed of tetramethylammonium chloride (TMAC) and oxalic acid dihydrate (OA) for a dual closed‐loop process to recycle LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode of spent LIBs. The binding energy between DESs and Li/Ni/Co/Mn ions were shown to critically influence metal leaching efficiency, implying that DESs with higher binding energy exhibited superior extraction performance. DES TMAC‐OA was screened out as optimal potential, and then followed by experimental validations to achieve the leaching of valuable metals from spent NCM811 cathode powder in a much milder condition (80°C, 30 min) with high efficiency. Combined with the coordination regulation of water and ethanol, a high selectivity separation of Li and Ni/Co/Mn can be achieved to regenerate high‐value precursors of NCM811 with both high purity and yield. The regenerated precursors can be used to produce new NCM811 with considerable electrochemical performances. More importantly, DESs can be perfectly regenerated and recycled many times, indicating that the process is cost‐effective and eco‐friendly. Such a strategy provides a feasibility basis to demonstrate a promising potential of DESs in the green recovery and recycling of valuable materials from spent LIBs, therefore benefiting the circular economy and the sustainable management of electronic waste.