Green molten salt modification of cobalt oxide for lithium ion battery anode application

The clean and low-cost preparation of advanced materials for green energy storage applications is a critical step towards sustainable development. Here, the rapid modification of CoO in molten salt is proposed as a low-cost approach for the scalable preparation of Co-based oxides with enhanced Li-storage performance. The phase evolution of CoO upon molten salt treatment is investigated by X-ray diffraction (XRD), electron microscopy, N2 adsorption–desorption and Raman spectroscopy. The molten salt treatment of CoO under dry and humid Ar atmosphere leads to the formation of dual-phase structured CoO/Co3O4 and Li0.065Co0.935O, respectively. High resolution transmission electron microscopy and fast Fourier transform analysis of samples after Li insertion and extraction process confirm the formation of nanostructured Co-Li2O. The Co phase formed from CoO/Co3O4 and Li0.065Co0.935O is found to have hexagonal close packed (hcp) and face central cubic (fcc) structure, respectively. The Li-storage performances of these materials are correlated to their structural/microstructural characteristics. This article presents a simple, scalable and environmentally-friendly approach for modification of Co-oxide materials for lithium ion battery anode applications.