Hydrogen storage, thermodynamic, structural, elastic, electronic and optical attributes of (Mg/Ca/Sr)₂FeH₆ with multiple potentials: A pathway toward efficient renewable energy solutions

Hydrogen storage is the technique of keeping hydrogen for use in energy applications, which is critical in the shift to sustainable energy. Innovative materials, such as metal hydrides, assure storage system efficiency and safety. In this paper, the physical traits of (Mg/Ca/Sr) 2 FeH 6 are examined by employing the different potentials. The optimization curves for each hydride reveal complete structural stability, and the obtained optimized lattice constants are 6.34, 6.98 and 7.39 Å. The stress–strain compliance matrix is reduced to C[Formula: see text], C[Formula: see text] and C[Formula: see text] to obtain the mechanical properties of (Mg/Ca/Sr) 2 FeH 6 . The electronic properties reveal direct bandgaps for Z 2 FeH 6 (Mg/Ca/Sr) 2 FeH 6 with both potentials. The optical properties revealed that these hydrides are extremely useful in optical devices such as ultraviolet-based lenses and anti-reflective coatings. The hydrogen storage capacities for the studied hydrides depict that Mg 2 FeH 6 has a high volumetric density of 78.46 gH 2 /L and a superior hydrogen capacity of 5.15[Formula: see text]wt.% with a desorption temperature of 221.4[Formula: see text]K, making it an effective hydrogen storage material as compared to Ca 2 FeH 6 and Sr 2 FeH 6 . These materials demonstrate the ability to adjust hydrogen storage capabilities via compositional modifications. Their various properties make them suitable options for certain hydrogen storage requirements in renewable energy systems.