First-principles study of structural, electronic, optical and hydrogen storage properties of LiXH3 (X = As, Se, Te) perovskites

Hydrogen storage is a key challenge in the transition to clean energy, with solid-state systems offering safer, more compact alternatives to compressed or liquefied hydrogen. However, achieving both high storage capacity and favorable desorption temperatures remains a limitation. In this work, we employ density functional theory (DFT) to investigate the structural, electronic, optical, and hydrogen storage properties of LiXH 3 (X = As, Se, Te) perovskite hydrides. Structural optimization confirms dynamic and thermodynamic stability, with lattice parameters increasing along the X = As → Te series. Electronic band structures and density of states reveal metallic behavior, enabling potential electronic conductivity beneficial for energy systems. Optical property analyses-including dielectric function, refractive index, and absorption coefficient-highlight strong light–matter interaction, supporting possible optoelectronic applications. Hydrogen storage performance, assessed via gravimetric (C wt% ) and volumetric (ρ vol ) capacities, yields 3.57 wt%, 3.41 wt%, and 2.20 wt%, and 89.16, 81.60, and 66.00 g H 2 /L for LiAsH 3 , LiSeH 3 , and LiTeH 3 , respectively, with the latter satisfying the 2025 U.S. DOE target. Despite these favorable characteristics, the desorption temperatures-534.15 K (As), 813.92 K (Se), and 1063.42 K (Te)-are relatively high, limiting practical hydrogen release. Nevertheless, the combination of metallic conductivity, low decomposition enthalpy, and structural robustness suggests potential utility in composite hydrogen storage systems or as catalytic enhancers. Strategies such as transition metal doping, catalyst incorporation, and nanoscale confinement are proposed to address desorption challenges and improve hydrogen release kinetics. These findings confirm that LiXH 3 perovskite hydrides offer tunable performance and hold promise for next-generation solid-state hydrogen storage technologies. • Confirmation of structural and thermodynamic stability across all compounds • A metallic nature in electronic structure, suggesting applicability in energy and electronic systems • Strong optical absorption characteristics, supporting potential in optoelectronic applications • Gravimetric and volumetric hydrogen storage capacities that meet or exceed the US-DOE 2025 targets • Detailed desorption temperature analysis, revealing tunable release properties linked to the X-site atom