Exploring the structural, electronic, mechanical, magnetic and optical properties of Cs-based hydride-perovskites CsXH3 (X = Cr, Mn) for hydrogen storage application

Low cast hydride-perovskites are more efficient in power conversion and for energy storage. Here in, structural
investigation, electronic, mechanical and optical properties of hydrogen based CsXH3 (X = Cr, Mn) compounds
using the density functional theory. The result shows that both materials crystallize into cubic structure. The
thermodynamic and dynamic stabilities are conformed through formation energy and phonon dispersion curve.
The optimized lattice constants are 3.52 Å and 3.54 Å for CsCrH3 and CsMnH3 respectively. Both materials are
found to be half metallic in nature. IR-Elast package are used to obtain elastic constants. The elastic study
presents that both materials are ductile and have anisotropic nature. The optical parameters are studied in the
range of 0–10 eV. The optical results show that both materials have an excellent optical absorption. The values
obtained of gravimetric hydrogen storage capacity for these compounds are 1.55 % and 1.58 % for CsMnH3 and
CsCrH3 respectively indicating that these materials can be an excellent candidate for hydrogen energy storage.