Rational analysis applied to calculate the unknown stoichiometry of Li-ternary oxides blended to Li-mono oxides in cathode material mixtures

Abstract

In this study, a method to calculate the unknown stoichiometry of a LiCoxNiyMnzO2 ternary oxide present in a cathode material mixture of Li-ion batteries is proposed. X-ray diffraction (XRD) and fluorescence (XRF) data were employed in a set of linear equations established by a rational analysis based on the relative weights and concentrations of the compounds and elements present in the mixture. The method was validated on a previously prepared LiCo0.22Ni0.51Mn0.27O2 and LiCoO2 mixture (in a 4:1 mass ratio) and applied to three other mixtures composed of a LiCoxNiyMnzO2 and Co and Mn Li-mono oxides. Measured X-ray diffraction patterns, simulated by Rietveld refinements, and crystallographic parameters are provided in detail for all mixtures. The method’s applicability to other mixtures than the Li-ternary and Li-mono oxides here presented are suggested, showing its enlarged scope.