A first-principles study to investigate the physical properties of Sn-based hydride perovskites XSnH3 (X = K, Li) for hydrogen storage application

Abstract

Based on density functional theory, the present study used the Cambridge serial total energy package code to figure out the structural, electronic, magnetic, optical, and mechanical properties of perovskite hydrides XSnH3 (X = K, Li). The band gap, total density of states, and partial density of states of the hydrides under consideration have been calculated, confirming the metallic behavior via the overlapping of the conduction and valence bands with a zero-band gap. The XSnH3 lattice parameters, determined using generalized gradient approximations, are 4.3 Å for KSnH3 and 4.1 Å for LiSnH3. Both of these materials are found to be hard, antiferromagnetic, and anisotropic in nature. The Poisson's ratio indicates that LiSnH3 is brittle while KSnH3 is ductile. The B/G ratio also confirms the brittleness of LiSnH3 and the ductility of KSnH3. The hydrogen storage capacity of KSnH3 and LiSnH3 is calculated to be 1.88 wt % and 2.35 wt %. Both materials have the potential to store hydrogen, as evidenced by the storage properties, but it is determined that LiSnH3 is the superior material to utilize for use in applications involving hydrogen storage.