Revolutionizing hydrogen storage: A first-principles investigation of hydrides double perovskites X2SiH6 (X = Mg, Ca, Sr) for structural, optoelectronic, and mechanical properties

초록

Storing hydrogen remains a major difficulty in developing clean energy solutions. This has led to research on new, lightweight hydrides that have both good stability and a high capacity for storage. This study uses firstprinciples density functional theory (DFT) computations to thoroughly analyze the structural, hydrogen storage, electronic, optical, and mechanical properties of X2SiH6 (X = Mg, Ca, Sr) hydrides. All the compounds showed both thermodynamic and mechanical stability, as shown by negative formation energies and elastic constants that met Born's requirements. The projected gravimetric storage capacities of 7.31 wt% for Mg2SiH6, 5.29 wt% for Ca2SiH6, and 2.89 wt% for Sr2SiH6, along with desorption temperatures ranging from 496 to 511 K, indicate their practical applicability in facilitating reversible hydrogen release. The electronic structure analysis shows metallic properties, which might help hydrogen adsorption and desorption happen quickly. At the same time, optical studies demonstrate high dielectric constants and strong absorption features, making these materials suitable for energy-related optoelectronic applications. The mechanical investigation indicates that the material behaves in a ductile way, which is mainly due to ionic bonds. Among the materials tested, Mg2SiH6 is the most promising for hydrogen storage, mainly because of its high storage capacity and its balanced structural and functional features. These discoveries provide useful insights into hydridosilicate-based perovskites, which could help in building new solid-state hydrogen storage technologies.

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