Multi-components Recycling of Cathode Material from Spent Lithium-Ion Batteries: In Situ Reduction Mechanisms and Leaching Kinetics

The rapid expansion in the deployment of lithium-ion battery (LIBs), driven by the widespread adoption of electric vehicles and renewable energy storage systems, has created an urgent demand for efficient recycling technologies to recover valuable metals and mitigate environmental risks. This study proposed a novel recycling strategy for the cathode material, integrating in situ thermal reduction, aqueous leaching, and selective separation. Reduction experiments and thermodynamic calculations revealed that the LiCoO2 underwent sequential aluminothermic and carbothermic reduction at above 500°C, forming Co, CoO, LiAlO2, and Li2CO3 as the main products. Microstructural analysis confirmed the progressive formation of nanoflower-like Co/CoO aggregates at elevated temperatures. Water leaching achieved a lithium recovery rate over 90%, and the kinetic analysis demonstrated that the process followed a mixed-control model with an expression of 1/3ln(1 − x) + (1 − x)− 1/3− 1 = 0.035exp(− 7.4/RT)t. Based on the reduction and leaching behaviors, a comprehensive recovery route was established to recover Li3PO4, CoC2O4·2H2O, and Al(OH)3 products. This work provided a concise and technically viable pathway for multi-components recovery from cathode material, contributing to the development of a sustainable circular economy for critical metals.