Recycling lithium and cobalt from LIBs using microwave-assisted deep eutectic solvent leaching technology at low-temperature

With the rapid development of electric vehicles and the large-scale energy storage market in recent decades, recovering valuable metals from spent LIBs has become challenging. Here, we proposed a reliable microwave-assisted deep eutectic solvents (DES) hydrometallurgy leaching method for leaching Li and Co from LiCoO2, which achieved efficient recovery at low temperatures with a low viscosity. The Li and Co extraction efficiency were close to 100% under the optimal leaching conditions of the temperature of 70 °C, leaching time of 10 min, the liquid-solid ratio of 5:0.1 g/g, and water content 10 wt% in choline chloride-formic acid DES. Furthermore, the Co could be recycled as Co3O4 by adding saturated sodium carbonate solution through the precipitation-calcination process. The addition of water can effectively reduce the viscosity of this DES and promote its flow properties. The study contains positive implications for the industrial application of eutectic solvents in the recycling of lithium-ion batteries.