The application of deep eutectic solvents in lithium-ion battery recycling: A comprehensive review

The extensive use of lithium-ion batteries (LIBs) in new electric vehicles has effectively alleviated the problems of insufficient oil and gas resources and environmental pollution. It is of great significance to realize the goals of "carbon neutrality" and "carbon peaking." As the key and last link in the use of power batteries, recycling waste LIBs is conducive to realizing resource return and avoiding pollution and potential risks of toxic and harmful substances in the environment. With the efforts of many researchers, the harmless treatment and resource re-covery process of spent LIBs has been maturing. In recent years, some new recycling processes have appeared frequently to solve the problems of high energy consumption and secondary pollution in the traditional approach. Among these new technologies, green and inexpensive deep-eutectic solvents (DESs) have been particularly attractive due to their excellent selectivity and leaching efficiency. This review summarizes the dissolution mechanism of valuable metals from LIB cathode materials using DESs. At the same time, the ad-vantages and challenges faced by DESs in cathode material recycling were analyzed, and an outlook was pre-sented for the future development of DESs in the field of battery recycling.