Facile Gram-Scale Synthesis of Co(3)O(4) Nanocrystal from Spent Lithium Ion Batteries and Its Electrocatalytic Application toward Oxygen Evolution Reaction

In this study, we demonstrate a new approach to easily prepare spinel Co(3)O(4) nanoparticles (s-Co(3)O(4) NPs) in the gram-scale from the cathode of spent lithium ion batteries (SLIBs) by the alkali leaching of hexaamminecobalt(III) complex ions. As-obtained intermediate and final products were characterized with powder X-ray diffraction (PXRD), Ultraviolet-Visible (UV–Vis), Fourier transform infrared (FTIR), and Transmission electron microscopy (TEM). Additionally, the synthesized s-Co(3)O(4) NPs showed better electrocatalytic properties toward the oxygen evolution reaction (OER) in comparison to previously reported Co(3)O(4) NPs and nanowires, which could be due to the more exposed electrocatalytic active sites on the s-Co(3)O(4) NPs. Moreover, the electrocatalytic activity of the s-Co(3)O(4) NPs was comparable to the previously reported RuO(2) catalysts. By taking advantage of the proposed recycling route, we would expect that various valuable transition metal oxide NPs could be prepared from SLIBs.