DFT‐Based Investigation of Physical Properties for Multifunctional Potential and Hydrogen Storage Application of Lithium‐Based Triel LiX ₃ H ₈ (X = B, Al, Ga, In) Hydrides

ABSTRACT This work aims to explore physical properties of lithium‐based triel hydrides (LiX 3 H 8 , where X = B, Al, Ga, In) to investigate their potentials for multifunctional purposes including hydrogen storage capacities. These calculations highlight structural, optoelectronic, thermodynamics and mechanical properties measured by DFT‐based first principles framework, which utilizes GGA‐PBE approximation and density functional perturbation theory for thermodynamic properties. The structural analyses have revealed the strong ionic character of Li with the surrounding elements, while the H–X bonds exhibit mixed ionic–covalent behaviors. The differences in bonding are primarily influenced by the variations in the atomic masses of the X atoms (X = B, Al, Ga, In). These hydrides have exhibited wide band gap values of 6.122, 4.082, 5.243, and 4.995 eV for LiX 3 H 8 (X = B, Al, Ga, In) respectively, making them to fall in insulator type. These characteristics shift their optical activity toward UV‐region of incident radiation as evidenced by high value of α(ω) (10 5 cm −1 ), along with dielectric function ε 1 (ω) and refractive index n(ω). Outcomes indicate their transparent behavior in this region, highlighting their potentials for UV photodetectors. These materials are dynamically and mechanically stable with ductile nature, and exhibit significant anisotropy in all dimensions, as revealed by thermodynamic and mechanical properties. The calculated values of hydrogen storage gravimetric capacities are 17%, 8.41%, 3.60%, and 2.24%, while volumetric densities are 112, 109, 105, and 98 g/L for LiX 3 H 8 (X = B, Al, Ga, In) respectively, indicating that LiB 3 H 8 and LiAl 3 H 8 exhibit strong potential for hydrogen storage applications.