Sustainable approach to cobalt recycling: Levulinic acid leaching of waste lithium-ion battery cathode materials

The global consumption of lithium-ion batteries (LIBs) has increased significantly due to the widespread application of electronic devices and electric vehicles. These batteries contain valuable metals, among which cobalt is a critical component. As a strategic material, it is desirable to recover cobalt from spent LIBs, thereby reducing reliance on primary resources. This study presents a sustainable recycling method that utilizes levulinic acid, a biomass-derived organic acid, in combination with hydrogen peroxide for the recovery of cobalt, with analysis conducted via UV-Visible spectrophotometry. The process specifically targets cobalt recovery from the cathode material of waste LIBs sourced from mobile phones. Key experimental parameters including acid concentration, solid-to-liquid (S/L) ratio, reaction time and temperature were systematically optimized. Under optimal conditions of S/L ratio of 1:50 and 80 °C, over 92 % of the cobalt was successfully leached. Complete cobalt leaching was observed at an S/L ratio of 1:500, demonstrating the high leaching capability of the system. The results demonstrate that levulinic acid is both an efficient and environmentally benign leaching agent for critical metal recovery. This approach aligns with circular economy principles by utilizing a renewable, waste-derived leachant and offers a promising green pathway for LIB recycling.