| Summary: | 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, LiCoO2, into easily separable lithium and nano-sized cobalt species by grinding LiCoO2 with NaBH4. The optimum lithium leaching rate of nearly 100% can be achieved from the sample milled at NaBH4 to LiCoO2 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 LiCoO2. CoO or metallic Co is produced when different NaBH4 dosage is applied. Whereas lithium is released as soluble LiOH. The results also prove the role of NaBH4 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.
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