High pressure phase transition in super-cell LiBH4: An ab initio prediction

LiBH₄ which have attracted considerable attention from researchers due to the crystal structure characteristics is a metal hydride that can bind four hydrogen atoms. LiBH₄ which has high gravimetric and volumetric hydrogen density shows phase transitions at high pressures. In this regard, we created and analyzed LiBH₄ structure based on the first principles calculations, and then obtained the super-cell LiBH₄ structure. We achieved the phase transitions up to 20 GPa pressure with 2 GPa regular intervals for the super-cell LiBH₄. We observed the Pnma to Pnma*, Pnma* to P2₁/c, and P2₁/c to C2/c phase transitions and calculated the volume contractions accompanying these phase transitions. According to the obtained volumetric values, one can conclude that LiBH₄ can minimize the volumetric requirements of the hydrogen storage for systems that can be used at high pressures. Thus, the hydrogen storage capacity of LiBH₄ may increase at particular phases.