A DFT study for physical properties and hydrogen storage capability of indium-based hydride perovskites XInH3 (X = Li, K) for hydrogen storage application

The physical properties and hydrogen storage capability of indium-based hydride perovskites XInH3 (X = Li, K) have been assessed in the present study. The HSE06 hybrid functional inside the CASTEP code based on DFT is used for the investigation of both materials. Both the compounds are found thermodynamically stable which is confirmed by the phonon dispersion curves. The negative values of the cohesive energy also show that both the materials are thermodynamically stable. Both the materials have zero band gap and possess metallic nature with the lattice constant values of 4.37 and 4.32 Å for LiInH3 and KInH3, respectively. The spin polarized band structure and density of states show that both the materials have antiferromagnetic nature. The optical properties show that both materials have a higher absorption and conductivity in the lower energy region. LiInH3 possesses higher values of static reflectivity and refractive index than KInH3. Both the materials are found mechanically stable, anisotropic, hard, and ductile in nature. The value of gravimetric ratio is found to be 2.42% and 1.92% for LiInH3 and KInH3, respectively. Both the materials can store sufficient hydrogen, however, LiInH3 is recommended as a preferred material for hydrogen storage application.