Structural and elastic properties of LiBH4 for hydrogen storage applications

Structural and elastic properties of LiBH4 in the orthorhombic structure were investigated using both the norm-conserving pseudopotentials and full potential within the general gradient approximation (GGA) in the frame of density functional theory. The Orthorhombic LiBH4 phase is found to be mechanically stable at ambient pressure. The calculated linear bulk moduli are found to be in good agreement with the experimental values reported in the literature. Shear and Young’s moduli as well as Poisson’s ratio for ideal polycrystalline LiBH4 are also calculated. According to the obtained results, LiBH4 can be classified as brittle material. A Debye temperature of 1272 K was also calculated using theoretical elastic constants.

► The elastic constants of LiBH4 are determined for the first time in this study.
► The LiBH4 is harder than any MBH4 compounds.
► The calculated Debye temperature was found higher compared to that of MBH4 series.
► The calculated Poisson’s ratio is smaller than the values reported for most MBH4.
► The LiBH4 compound is relatively stable against shear.