The mixed lithium-magnesium imide Li2Mg(NH)2 a promising and reliable hydrogen storage material

A statistical theory of the structural phase transformations of the imide Li2Mg(NH)2 has been developed, the formation of which is accompanied by the release of free hydrogen. The standard Gibbs free energy formation of the imide's three phases: α, β, γ are calculated. Their dependencies on composition, temperature, pressure, and energy are found. Plots of concentration dependences of the free energy values of these phases are constructed for different temperatures, according to which the imide state diagram is established. Isotherms, isobars and isoplets are investigated. The possibility of hysteresis effect for α and β phases is shown. The results of the calculations are compared with the experimental data.