The first principles investigation of free‑lead perovskite-type hydrides CsXH3 (X = Sc, Y) for hydrogen storage application

Abstract

Utilizing density functional theory (DFT), we carried out a comprehensive analysis of the novel CsXH₃ (X: Sc and Y) perovskite hydride's structural, mechanical, electronic, magnetic, thermodynamic, optical, and hydrogen storage properties. Through cohesive energy and elastic moduli calculations, we found that the CsXH₃ compounds demonstrated both mechanical and thermal stability. For Sc and Y, the lattice constants in the crystal structure of CsXH₃ (X: Sc and Y) compounds are 3.376 Å and 3.525 Å, respectively. Currently, the overall observations of band structure and electronic density of states are used to evaluate the metallic character of these compounds. These substances appear to be malleable materials, according to the B/G ratio (Pugh's ratio) study. Subsequent analysis indicated that the majority of their bond types are ionic. These compound features have led to the conclusion that they are non-magnetic order conductors. Furthermore, these materials have optical properties such as refractive index, dielectric function, absorption, and conductivity that show promise. According to our predictions, CsScH₃ is a better hydride with exact optical characteristics. Vibrational stability of these crystalline materials was studied using molecular dynamics simulations and phonon dispersion curves. In addition, the study evaluated the CsXH₃ compounds' ability to store hydrogen, resulting in 1.67 wt% for CsScH₃ and 1.35 wt% for CsYH₃. This discovery opens up new possibilities in the realm of hydrogen storage materials as it is the first analysis of CsXH₃ perovskite hydrides.