Use of Microwave-Assisted Deep Eutectic Solvents to Recycle Lithium Manganese Oxide from Li-Ion Batteries

To realize efficient recycling of lithium manganese oxide (LMO) from spent Li-ion batteries, microwave-assisted deep-eutectic solvent (DES) treatment is proposed. The effects of the DES, temperature, time, and liquid/solid (L/S) ratio on the leaching efficiency were studied by orthogonal and single-factor experiments. The results of the orthogonal experiments indicated that the effects of each factor on the leaching of Li and Mn ions lay in the following order: DES > L/S ratio > temperature > time. The results of the single-factor experiments indicated that the leaching efficiencies of both Li and Mn ions reached 96% under the condition of choline chloride-oxalic acid (ChCl-OA), 15 min, 75 degrees C, and L/S ratio of 6 g/0.1 g. Microwave-assisted DES treatment is highly efficient for recycling LMO from Li-ion batteries, greatly decreasing the leaching time from several days to less than 1 h even at 75 degrees C in comparison with the traditional heating method.