Developing the insight for systematic exploration of hydrogen storage in RbMgF3

Abstract

In the present work, the density functional theory calculation has been performed for RbMgF3-xHx with GGA-PBE approximation implemented in CASTEP code. First time the structural, mechanical, electronic and optical properties of perovskite RbMgF3-xHx (x = 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.65, 1.80, 1.95, 2.25, 2.55, 2.85 and 3.0) has been investigated in details along with hydrogen storage applications. The results of formation enthalpy and elastic constants indicate that the materials are synthesizable. It has been found that the concentration of hydrogen storage decreases the elastic moduli and anisotropy whereas the bandgap becomes narrow because of the shifting of conduction band toward the fermi level. This indicates that hydrogen inclusion altered the electronic properties of the material and material can also be used in various optoelectronic devices alongwith hydrogen storage application. The crystal structure shifted from cubic to tetragonal during the hydrogen storage. The optical properties were thoroughly investigated between 0 and 10 eV. It has been found optical properties are enhanced with the doping concentration of hydrogen, which makes them good candidates for optoelectronic devices. The gravimetric ratio of hydrogen increased up to 2.61% with hydrogen incorporation. The presented material is an efficient material not only for opto-electronic applications but also for hydrogen storage as well.