Computational insights of double perovskite X 2 CaCdH 6 (X = Rb and Cs) hydride materials for hydrogen storage applications: A DFT analysis

Perovskite materials play a backbone role in materials science to investigate various applications including photocatalytic, photovoltaic, and hydrogen storage. Hydrogen storage is a modern technique to fulfill energy consumption and demands. We inspect the structural, hydrogen, electronic, optical, and thermodynamic properties of X 2 CaCdH 6 (X = Rb and Cs) perovskite substances for hydrogen (H 2 ) storage applications. The research shows substances have 225 Fm3m cubic natures and 40 atoms. The formation and cohesive energies of the examined structures show that X 2 CaCdH 6 (X = Rb and Cs) substances may be produced and are thermodynamically stable. Electronic characteristics indicate that substances are semi-metallic, with correspondingly indirect bandgap E g energies of 2.13 eV and 2.30 eV. The mechanical stability (Born stability), brittle (B/G = 1.22, 1.15 and alpha = 0.17, 0.18), hard (6.255, 5.481), and anisotropic (0.278, 0.171) of the X 2 CaCdH 6 (X = Rb and Cs) perovskite substances are demonstrated by the examined elastic values. The Debye temperature Theta D (289.395, 320.837)K, melting temperature T m (646.961, 650.714)K, acoustic velocities (v m , v l , v t ) m/s, minimum thermal conductivity K min (0.63, 0.75) (W/mK), and Gr & uuml;neisen parameter (18.121, 19.521) of substances are also computed by investigating their thermodynamic characteristics. Cs 2 CaCdH 6 and Rb 2 CaCdH 6 have gravimetric ratios of 1.39 wt% and 1.69 wt%, correspondingly. Our findings shed light on using double perovskites X 2 CaCdH 6 (X = Rb and Cs) as a hydrogen (H 2 ) storage substance.