Li-Ion Battery Cathode Recycling: An Emerging Response to Growing Metal Demand and Accumulating Battery Waste

Due to the accumulation of waste mobile devices, the increasing production of electric vehicles, and the development of stationary energy storage systems, the recycling of end-of-life Li-ion batteries (EOL LIBs) has recently become an intensively emerging research field. The increasing number of LIBs produced accelerates the resources' depletion and provokes pollution. To prevent this, the global communities are concerned with expanding and improving the LIBs recycling industry, whose biggest problems are either large gaseous emissions and energy consumption or toxic reagents and low recycling yields. These issues are most likely solvable by upgrading or changing the core recycling technology, introducing effective benign chemicals, and reducing cathode losses. In this review, we analyze and discuss various LIB recycling approaches, emphasizing cathode processing. After a brief introduction (LIB's design, environmental impact, commercialized processes), we discuss the technological aspects of LIB's pretreatment, sorting and dissolving of the cathode, separation of leached elements, and obtaining high-purity materials. Covering the whole LIB recycling line, we analyze the proven and emerging approaches and compare pyrometallurgy, hydrometallurgy, and cathode's direct restoration methods. We believe that the comprehensive insight into the LIB recycling technologies made here will accelerate their further development and implementation in the large-scale battery industry.