Determination of the figurative point trajectory on the phase diagram of NiO lithiation–oxidation process by x-ray diffraction and Compton scattering methods

Abstract

The positions of the figurative points on the triangular Gibbs phase diagram for the process of high-temperature synthesis of solid solutions Li yNi2− yO2 were determined for the first time using a combination of x-ray diffraction (XRD) and Compton scattering methods. The trajectory of the figurative point is built according to experimental data for temperatures of 650 and 750 °C. The ratios of the phases in equilibrium are found. It was established that, when the structure goes from rock salt to layered structures, the composition of the reagent mixture changes nonmonotonically: with an increase in the degree of ordering of the solid solution lattice, the sum molecular weight of the solid reagents increases. It has been shown experimentally that the combined use of XRD and Compton scattering makes it possible to carry out physicochemical analysis of the process and predict the final product.