Hydrogen presents a compelling solution to the growing energy scarcity and environmental problems as a clean and sustainable energy source. Among various storage methods, solid-state hydrogen storage holds promise but necessitates extensive investigation. However, to enhance the performance of these systems, metal hydrides with high gravimetric densities, favorable thermodynamics, and rapid kinetics are essential. The novelty of this work is the systematic comparison of the CaMg
2
FeH
8
and Be
2
MgFeH
8
hydrides by using the CASTEP calculation tool based on first-principles, which includes the assessment of hydrogen storage, structural, XRD, molecular dynamic simulations, electronic (Hybrid-HSE 06), Mulliken population analysis, optical, and thermodynamic properties of ZMg
2
FeH
8
(Z = Ca, Be) under 0, 35, and 70 GPa pressure for hydrogen storage applications. Structural investigation confirms structural stability, while XRD patterns confirm phase stability over varying pressure ranges. The calculated gravimetric capacities of CaMg
2
FeH
8
and BeMg
2
FeH
8
5.2837 wt% and 6.6343 wt%, respectively. CaMg
2
FeH
8
and BeMg
2
FeH
8
show the hydrogen desorption temperatures of 460.7 K and 476.4 K. Molecular dynamic simulations and thermodynamic analysis validate dynamical and thermal stability under 0–70 GPa pressure. Electronic properties reveal that both ZMg
2
FeH
8
(Z = Ca, Be) exhibits the semiconductor nature. Optical study indicates significant absorption in the UV spectrum. These findings present ZMg
2
FeH
8
(Z = Ca, Be) compounds as strong candidates for hydrogen storage applications and a gateway for experimental researchers to the advancement of sustainable energy technologies.
Muhammad Adnan Samhi, Shafaat Hussain Mirza, Sikander Azam et al.· Scientific Reports· 0 citations
Next-generation clean-energy technologies seek efficient solid-state energy storage materials for hydrogen-based energy systems that exhibit thermodynamically stable properties and multifunctional optoelectronic performance. In the current article, the structural, hydrogen-storage, mechanical, electronic, optical, thermodynamic, and photocatalytic properties of the A
2
LuCuH
6
(A = Li, Na, K) cubic double perovskite hydrides are systematically investigated using first principles density functional theory calculations. The optimized lattice constant gradually rises from 7.78 Å in Li
2
LuCuH
6
to 7.94 Å in Na
2
LuCuH
6
and 8.18 Å in K
2
LuCuH
6
, and the bulk modulus gradually reduces from 43.48 to 39.29 GPa, showing gradually increasing lattice softening. Negative formation enthalpies of -43.08, -48.71, and − 54.99 kJ/mol verify their thermodynamic stability. The gravimetric hydrogen-storage capacities are recorded as 2.34, 2.08, and 1.87 wt%, while the volumetric capacities are 21.33, 20.06, and 18.35 gH
2
/L for Li, Na, and K-based compounds, respectively. The computed hydrogen desorption temperatures are 329.61, 372.54, and 420.73 K, which show tunable hydrogen-release behavior. The indirect semiconducting band gaps in the range of 1.46–2.01 eV at ambient pressure with strong optical absorption in the visible-UV range. In addition, the favorable band-edge alignment is indicative of photocatalytic suitability for overall water splitting, and the pressure-dependent thermodynamic parameters indicate lattice rigidity and a decrease in anharmonic effects under compression, which demonstrates the multi-functional energy potential of these hydride perovskites.
Ali Mustafa Khan, M. U. Sohaib, Sikander Azam et al.· Scientific Reports· 0 citations
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