Electrochemical and quantum chemical studies of the reactions of transition metals M (M = Co, Fe and Ni) with LiF and Li2O

It has been a puzzle that transition metals can unexpectedly react with lithium-based matrixes of LiF and Li₂O in the potential versus Li/Li⁺ range from 0.01 to 3.5 V at room temperature. The electrochemical and theoretical investigations on the reactions of transition metals M (M = Co, Fe and Ni) with LiF and Li₂O were carried out. The electrochemical reactivity of metal cobalt with LiF and Li₂O has been examined by the discharge and charge, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. Density functional theoretical calculation results suggested that the stable compounds MLiF and MLi₂O could be formed by the insertion of transition metal (M) in lithium-based matrixes with exothermic as an intermediate. The theoretical calculations provide an understanding in chemical reaction of M with LiF and Li₂O. The small molecular or clusters reaction may play an important role in the electrochemical reaction of metal with transition Li₂O or LiF, which could be used to explain for the unexpectedly reaction of transition metal with LiF and Li₂O.