First-principles study on interfacial property in MgB2-based reactive hydride composites

The underlying physico-chemical interactions between transition metal-based boride particles that formed during the dehydrogenation process and MgB2 in 2LiBH4+MgH2 reactive hydride composite at the atomic scale are still unknown. In this work, the properties of the TiB2/MgB2 interface were investigated by first-principles calculations utilizing density functional theory (DFT). Taking the two terminations of both MgB2 and TiB2 as well as four different stacking sequences into account, energies of the TiB2 and MgB2 (0001) surfaces as well as the work of adhesion and the electronic structure of the interfaces were studied. The results show that the interface between the B-terminated MgB2 (0001) surface and the Ti-terminated TiB2 (0001) surface is the energetically most favorable among all four stacking options and possesses the largest work of adhesion. Our results further show that the TiB2 particles possess good nucleation potency for MgB2 particles from the thermodynamic perspective.