Ab-initio study of the structural, optoelectronic, magnetic, hydrogen storage properties and mechanical behavior of novel combinations of hydride perovskites LiXH3 (X = Cr, Fe, Co, & Zn) for hydrogen storage applications

LiXH3 (X = Cr, Fe, Co, & Zn) hydride type perovskites have been studied by applying density functional theory (DFT), and their structural, optoelectronic, magnetic, hydrogen storage, and mechanical properties have been calculated. The results show that these materials are synthesizable for hydrogen storage applications. The energy band structures as well as total density of states (TDOS) and partial density of states (PDOS) unveil that LiCrH3, LiCoH3, and LiZnH3 possess metallic character, while LiFeH3 exhibits semiconducting behavior. The lattice constants are calculated by applying PBE + GGA functional which are listed as 3.4940, 3.1791, 3.6343, and 3.7132 Å for LiXH3 (X = Cr, Fe, Co, & Zn), respectively. In order to manage the restriction of PBE + GGA functional, the lattice constants are also calculated by applying hybrid HSE06 functional which are found to be 3.3126, 2.9675, 3.1531, and 3.4018 Å for LiCrH3, LiFeH3, LiCoH3, and LiZnH3, respectively. The elastic stiffness constants show that these materials are mechanically and elastically stable and are deemed suitable as transportation materials in hydrogen storage devices. Moreover, mechanical parameters such as Poisson coefficient, Cauchy pressure, melting temperature, Young, Bulk, and Shear moduli have been calculated. Dielectric constants, refractive index, optical conductivity, absorptivity, and energy loss function have been determined to seek an optical behavior of the considered perovskites for hydrogen storage applications. The present study is the first theoretical approach to the contribution for future exploration of these materials.