Pretreatment options for the recycling of spent lithium-ion batteries: A comprehensive review

The production of lithium-ion batteries (LIBs) is increasing rapidly because of their outstanding physicochemical properties, which ultimately leads to an increasing amount of spent lithium-ion batteries reaching their end-of-life (EOL). Pretreatment of the discarded batteries is an indispensable part of recycling spent lithium-ion batteries. The batteries contain toxic chemicals and high-value metals that must be recycled to promote environmental protection and sustainability. This paper provides an overview of the current pretreatment methods employed in the recycling of spent LIBs. In particular, the article reviews various options (mechanical, chemical, and thermal pretreatment options) that can be adopted for the pretreatment of spent lithium-ion batteries and puts forward the recommendations for future research and development that will enable more efficient and cleaner technologies for recycling spent LIBs. The review emphasizes the safe pretreatment of the spent LIBs and provides an overview of the consequences of the individual pretreatment steps on the recyclability of the materials to be recovered, and LiCoO2 was chosen as the reference as most studies in the literature focus on LiCoO2 cathode materials. However, discussions on other battery chemistries have also been incorporated into the scope of the review.