Principles-based investigation of lithium-based halide perovskite X2LiAlH6 (X=K, Mn) for hydrogen storage, optoelectronic, and radiation shielding applications.

Scientists devote their time and energy to studying and developing hydrogen storage devices to address the energy crisis and climate change. Because of this, investigations are conducted to reveal the optoelectronic, structural, bader charge, electronic charge density, and hydrogen storage properties of X 2 LiAlH 6 (X = K, Mn) within the framework of density functional theory, and calculations of the structural characteristics were carried out utilizing local and nonlocal, and hybrid functionals. An additional onsite Coulomb parameter (GGA + U), which includes the Hubbard parameter, was used to apply the potential. Calculations based on the Kramer-Kroning principle were used to determine the dielectric function, refractive index, extinction coefficient, and energy loss function. The results indicate that K 2 LiAlH 6 and Mn 2 LiAlH 6 are highly suitable for hydrogen storage applications. The gravimetric ratios of hydrogen storage capacities for both investigated materials are 5.2 wt %, and 7.5 wt %, respectively. The interaction of the Mn-d, Li-s, K-s, and H-s/p orbitals was the cause of hybridization, according to the optoelectronic characteristics. Compound stability is indicated by the negative computed formation energy of the materials under investigation. The electronic charge density analysis showed a mixed-bond semiconductor with low ionicity and high covalence. In addition, the radiation shielding properties of Mn 2 LiAlH 6 and K 2 LiAlH 6 were investigated using Phy-X software, showing promising results in linear attenuation, half-value layer, and mean free path, particularly for Mn 2 LiAlH 6 due to its higher atomic number. This groundbreaking study represents a pioneering computational exploration of X 2 LiAlH 6 , offering promising advancements for future research in hydrogen storage applications. • The structural properties of X 2 LiAlH 6 were analyzed using DFT, revealing promising stability metrics. • Mn 2 LiAlH 6 shows enhanced radiation shielding due to its higher atomic number and interaction effects. • Hydrogen storage capacity for K 2 LiAlH 6 and Mn2LiAlH6 was calculated to be 5.2 wt % and 4.7 wt %, respectively. • Phy-X software simulations revealed Mn 2 LiAlH 6 's superior shielding performance against gamma rays. • Optical properties demonstrated high absorption coefficients, indicating potential for energy applications. [ABSTRACT FROM AUTHOR]