Experimental study of cobalt oxide recovery from spent batteries

In this work, cobalt oxide was primarily recycled from spent lithium- ion battery at optimum condition by using hydro-metallurgical method. Based on the preliminary results from X-ray diffraction (XRD) analysis, there are cobalt oxide 81.89% and nickel oxide 0.11%, as typical nickel compounds in spent lithium- ion batteries. The optimum recycling condition of cobalt oxide from spent battery sample (0.5 g) by leaching is as follow: the use of 18.62 mL (0.607 mole) hydrochloric acid and 2 mL (0.065 mole) hydrogen peroxide at 50°C for 2 hours. The X-ray diffraction (XRD) spectrum confirms the recycling of cobalt oxide. In the second step, cobalt oxide was converted into insoluble cobalt carbonate intermediate. Consequently, cobalt nanoparticles were synthesized via liquid phase reaction by using two separate reducing agents; hydrazine or sodium boro-hydrate, while proceeding different routes. The molecular and crystal structures of the prepared cobalt nanoparticles were approved by X-ray diffraction. The morphology of surface and size characterization of nanoparticles by scanning electron microscopy (SEM) indicated that spherical shape cobalt nanoparticles with maximum 30 nm and 50 nm diameter were successfully synthesized by using hydrazine and sodium boro-hydrate reducing agents respectively.