Recover lithium and prepare nano-cobalt from spent lithium ion batteries using a one-pot mechanochemical reaction

Recovery valuable metals such as lithium and cobalt from spent lithium ion batteries presents great economic significance as well as environmental benefits. The present work explores a mechanochemical reaction of the most widely used cathode materials, LiCoO 2 , into easily separable lithium and nano-sized cobalt species by grinding LiCoO 2 with NaBH 4 . The optimum lithium leaching rate of nearly 100% can be achieved from the sample milled at NaBH 4 to LiCoO 2 mass ratio at 2.5:10 (g/g), milling time for 90 min when Ball-to-powder mass ratio is fixed at 65:1 (g/g), and rotary speed of the planetary ball mill fixed at 400 rpm. The crystal information suggests the grain refinement and chemical transformation of LiCoO 2 . CoO or metallic Co is produced when different NaBH 4 dosage is applied. Whereas lithium is released as soluble LiOH. The results also prove the role of NaBH 4 dosage in determine the reaction path. Microscopic observation confirms the grain refinement during the milling process. Nano-sized cobalt species are also observed. This solid phase mechanochemical reaction provides an effective and short route from waste to potentially high-value added material.