Direct Recycling of Lithium-Ion Batteries Using Hydrothermal Relithiation

This study aims to develop a direct recyclingRecycling process of spent lithiumLithium-ion batteries (LIBs) from an electric vehicleElectric vehicles. In this direct recyclingRecycling process, the electric vehicleElectric vehicles battery pack is first discharged and disassembled to obtain the spent cathode material, which is then hydrothermally relithiated at 220 °C for 2 h followed by sinteringSintering at 850 °C for 4 h in air. The product after these steps is the regenerated cathode material, which is used to fabricate new LIBs to evaluate the electrochemical performance. The regenerated cathode material delivers an initial discharge capacity of 151 mAh g−1 at 0.33C (50 mA g−1) with a capacity retention of 91% after 50 cycles. By combining hydrothermal relithiationHydrothermal relithiation with sinteringSintering, lithiumLithium deficiency, structural defects, and electrochemical activity of the spent cathode material are successfully restored.