A comprehensive review on the pretreatment process in lithium-ion battery recycling

Abstract The worldwide demand for Li-ion batteries (LIBs) has risen sharply, and the number of spent LIBs is increasing proportionally. The current situation makes the recycling of spent LIBs indispensable for the conservation of the environment and the raw materials used in the LIBs. The pretreatment process in LIB recycling can enhance the recovery efficiency of the valuable elements in the LIBs and reduce the energy consumption in the subsequent processes. The pretreatment process has been adopted from the early stage of LIB recycling research, a large number of articles that focus on the pretreatment methods of spent LIBs have emerged over the last few years. Therefore, it would be appropriate to categorize various emerging methods in the pretreatment process and summarize the relevant literature in the current stage. This review focuses exclusively on the pretreatment process itself by comprehensively analyzing the relevant literature, which is unlike most review papers that covered the pretreatment process as a part of the general LIB recycling technology. We establish the scope and the sequence of the pretreatment processes, which are classified into discharge, dismantling, comminution, classification, separation, dissolution, and thermal treatment. The technology development and the current status of each category are discussed in depth.