First-principles calculations of structural, elastic and electronic properties of Li2B12H12

We investigate the structural, elastic and electronic properties of Li2B12H12 using the first-principles method. Our calculations show that the lowest energy structure of Li2B12H12 is monoclinic C2/m type. We take the monoclinic C2/m Li2B12H12 as a representative to carry out the corresponding theoretical studies. The independent elastic constants are successfully obtained from the strain energy-strain curve calculations. The Shear and Young's moduli, as well as Poisson's ratio for ideal polycrystalline Li2B12H12 are calculated. The shear anisotropic factors and elastic anisotropy of Li2B12H12 are analyzed. The Debye temperature and the average elastic wave velocity are derived from theoretical elastic constants. According to the obtained results, the monoclinic C2/m Li2B12H12 is found to be mechanically stable and brittle at zero temperature and zero pressure. Furthermore, the density of states and electron charge density distributions are studied. The insulator Li2B12H12 is a technologically interesting indirect hydrogen storage material for further studies. (C) 2014 Elsevier B.V. All rights reserved.