Solid-state NMR and thermodynamic investigations on LiBH4LiNH2 system

In this paper, Li2(BH4)(NH2) and Li4(BH4)(NH2)3 compounds were prepared through different synthesis approaches (ball milling, annealing treatment and liquid quenching) and characterized by X-ray diffraction and solid-state NMR. The thermal analysis of samples with various (LiBH4)1−x(LiNH2)x compositions (0 ≤ x ≤ 1) have been performed by High Pressure DSC. Lattice constants, chemical shifts and relative phase stability obtained by DFT turned out in good agreement with experimental data. On the basis of a combination of ab-initio calculations and experimental data, a thermodynamic assessment of the LiBH4LiNH2 system has been obtained using the Calphad method. Li2(BH4)(NH2) has been identified as a metastable phase and a peritectic melting of Li4(BH4)(NH2)3 compound has been established.