A high-efficiency and low-carbon strategy for selective lithium recovery from spent lithium-ion batteries: Combining mechanochemical activation with biomass reduction roasting

Biomass reduction roasting has attracted considerable attention as an emerging strategy for selectively recovering lithium from spent lithium-ion batteries (LIBs). However, the utilization of excessive roasting conditions in current practices results in significant energy consumption and C emissions, thereby hindering further development. Herein, we propose a novel recycling strategy that combines mechanochemical activation (MCA) with biomass reduction roasting. The optimized roasting conditions with MCA pretreatment achieve a 100 °C reduction in roasting temperature, a halving of biomass ratio and roasting time, compared to the case without activation. By analyzing the changes in physicochemical properties of mixed samples (cathode materials and biomass) under different activation conditions and their impacts, the action mechanism of MCA on biomass reduction roasting is revealed. The introduction of MCA pretreatment achieves milder roasting conditions by promoting homogeneous mixing and disrupting NCM crystal structures through the "pre-oxygen elements removal" process. Furthermore, mechanical treatment was applied to enhance the carbonated water leaching process. The results of sustainability analysis and economic evaluation demonstrate that the proposed recycling strategy not only reduces CO2 emissions and energy consumption but also generates considerable benefits. Overall, this high-efficiency and low-carbon recycling strategy provides a promising direction for the development of spent LIBs recycling technology.