Design and exploration of LiSc-based tetrahydro complex hydrides for advanced hydrogen storage and energy applications

This work presents thorough analyses of the structural, elastic, optoelectronic, thermodynamic and mechanical characteristics of mixed metal tetrahydro complex (LiScX 4 H[Formula: see text], or LiSc(XH 4 ) 4 , where X [Formula: see text] B, Ga, Al, and In) hydrides by using the GGA-PBE functional. The obtained indirect wide band gaps for LiScB 4 H[Formula: see text] (4.489[Formula: see text]eV), LiScGa 4 H[Formula: see text] (3.880 eV), LiScAl 4 H[Formula: see text] (3.665[Formula: see text]eV), and LiScIn 4 H[Formula: see text] (3.613[Formula: see text]eV) hydrides indicate their potential applicability in UV-optoelectronic devices (UV photodetectors, UV LEDs, and solar-blind detectors, etc.). In electronic localization function analysis, hydrogen atoms have exhibited vigorously localized areas with ELF values [Formula: see text]1.0, confirming their anionic nature (H − ) through charge transfer from lithium. According to optical properties, the dielectric function (4–6), refractive index (2–2.5), and high absorption (10 5 [Formula: see text]cm[Formula: see text]) of hydrides have shown pronounced responses in the Visible and near-UV ranges. The mechanical parameter ([Formula: see text]) of hydrides indicates ductile behaviors and anisotropic properties along the XY, YZ, and XZ axes. The DFPT approach is used to examine the thermodynamic properties, and the zero-point energies for LiScX 4 H[Formula: see text] hydrides are 8.629, 7.029, 6.798, and 6.431[Formula: see text]eV, respectively. The variation in zero-point energies shows solid bonding and atomic connections of hydrides. The calculated gravimetric hydrogen storage capacities (GHSC) are 14.5% for LiScB 4 H[Formula: see text], 4.7% for LiScGa 4 H[Formula: see text], 9.2% for LiScAl 4 H[Formula: see text], and 3.1% for LiScIn 4 H[Formula: see text]. These results indicate that these materials may be considered as potential candidates for hydrogen storage applications as well.