Identifying the nature of interaction between LiBH4 and two-dimensional substrates: DFT study with van der Waals correction

Abstract

Abstract Addressing the nature of interaction at the LiBH 4 −carbon interface is the key to unveiling mechanism for the carbon-facilitated desorption of lithium borohydride (LiBH 4 ). Density functional theory calculations, taking into account the long range dispersion forces, have been performed to explore the interaction between LiBH 4 , in the form of either a monomer unit or a crystalline bulk, and two-dimensional (2D) substrate, represented by graphene and hexagonal boron nitride. At the monomer−2D contact, the permanent dipole of LiBH 4 induces polarization of the π electrons of the 2D, and the resultant permanent dipole–induced dipole attraction becomes the main source of binding. At the bulk−2D interface, van der Waals attraction dominates the interfacial binding rather than the dipole–dipole attraction. The absolute values of the calculated interface energy match closely with the surface energy of pristine (0 0 1) LiBH 4 , hinting that the energy released by the formation of the interface has enough magnitude to overcome the surface energy of LiBH 4 .