Electro-optical properties, decomposition pathways and the hydrostatic pressure-dependent behaviours of a double-cation hydrogen storage material of Al3Li4(BH4)(13)

摘要

Electro-optical properties, the decomposition pathways and the pressure-dependent behaviours of Al3Li4(BH4)(13) have been investigated using a first-principle plane-wave pseudopotential method. Al3Li4(BH4)(13) is a kind of double-cation borohydride, consisting of distorted tetrahedral anions [Al(BH4)(4)](-) and cations [Li-4(BH4)](3+), which obeys the stability criteria of decomposition reactions. Herein, two possible decomposition reactions of the compound are proposed, which release 18 hydrogen molecules (about 12.03 wt%) in the first reaction and 24 hydrogen molecules (about 16.04 wt%) in the second reaction. On increasing the pressure on the structure, the lattice parameter, the volume of unit cell, the quasiparticle band gap and also enthalpy of the system decrease nearly monotonically; therefore, the acceptor levels gradually get filled and the Fermi level shifts upward. Results of computational investigations of the structural, electronic and thermodynamic parameters and their pressure-dependent behaviours indicate that Al3Li4(BH4)(13) has intriguing properties. Therefore, it would be a very promising material for hydrogen storage technology.