Efficient Recovery of Lithium and Cobalt from Spent LCO Using Mechanochemical Activation and Ammoniacal Leaching

In this study, we investigate the recovery of Li and Co from spent LiCoO2 cathodes of spent lithium batteries using a combined approach of mechanochemical activation (MA) and ammoniacal leaching. High-energy ball milling disrupts the layered structure of LiCoO2, introduces defects, and increases surface area, which strongly improves subsequent dissolution. Leaching experiments in an ammonia–ammonium sulphate–sulphite medium were optimized by varying the solid-to-liquid ratio, sodium sulfite concentration, and temperature. Under the best conditions (90 °C, 120 min, S/L = 10 g/L, 0.5 M Na2SO3), nearly complete recoveries were obtained: 99.5% Li and 96.5% Co. Kinetic modeling based on the shrinking-core model confirmed that dissolution of both metals is controlled by chemical reaction, with activation energies of 45.7 kJ·mol−1 for Li and 60.7 kJ·mol−1 for Co. Structural and morphological analyses (XRD, SEM) supported the enhanced reactivity of the activated material. The study demonstrates that MA coupled with optimized ammoniacal leaching provides an efficient process for LiCoO2 recycling, without using aggressive mineral acids and long treatment times.