First-principles density functional theory calculations were performed using CASTEP to investigate the physical and hydrogen storage properties of cubic ACaH
3
(A = Be, Mg, Sr, and Ba) hydrides and to determine how A-site cation identity influences their behavior. The optimized lattice constants of BeCaH
3
, MgCaH
3
, SrCaH
3
, and BaCaH
3
are 4.091, 4.193, 4.362, and 4.464 Å, respectively, while the corresponding formation energies are -0.702, -1.031, -1.408, and -1.455 eV/atom, indicating energetically favorable formation relative to the constituent elemental states. All four hydrides exhibit metallic electronic structures, with bands crossing the Fermi level, whereas charge density and population analyses reveal predominantly ionic metal hydrogen bonding with a limited covalent contribution. The cubic elastic stability criteria are satisfied throughout the series, while phonon calculations reveal composition dependent soft modes in the ideal cubic phases at 0 K. BeCaH
3
is the softest and most elastically anisotropic member and is the only ductile compound, whereas SrCaH
3
exhibits the highest shear resistance and stiffness. The gravimetric and volumetric hydrogen storage capacities are, respectively, 5.770 wt.% and 72.93 g H
2
L
-1
for BeCaH
3
, 4.470 wt.% and 67.90 g H
2
L
-1
for MgCaH
3
, 2.295 wt.% and 60.04 g H
2
L
-1
for SrCaH
3
, and 1.663 wt.% and 55.99 g H
2
L
-1
for BaCaH
3
. The corresponding lowest estimated desorption temperatures are 82.680, 150.596, 693.382, and 716.070 K, respectively. Across the series, the increasingly negative formation energy is accompanied by decreasing hydrogen storage capacity and a progressively higher temperature requirement for hydrogen release. Overall, A-site substitution strongly influences the hydrogen storage capacity and thermodynamic requirement for hydrogen release, supporting further experimental evaluation of these ACaH
3
hydrides particularly BeCaH
3
as solid state hydrogen storage materials.
Sahed Mahmud, Md Saiduzzaman, M. N. Khan et al.· Modern physics letters B· 0 citations
First‐principles density functional theory (DFT) computations were conducted to examine the structural, electrical, optical, mechanical, and hydrogen storage properties of the rare‐earth‐based perovskite hydrides XLiH3 (X = Tm, Yb). The cubic structures were optimized in space group Pm3¯m$Pm\bar{3}m$ with approximately equal lattice parameters (∼3.61 Å; ∼47 Å3). The stability of the cubic framework aligns with tolerance and octahedral factor criteria. Thermodynamic stability is evidenced by the negative formation energies of −0.489 and −0.456 eV/atom for TmLiH3 and YbLiH3, respectively. The electronic structure analysis demonstrates metallic characteristics, indicating improved electrical conductivity and efficient charge transfer. The compounds demonstrate strong mechanical, dynamic, and thermal stability, confirmed by standard elastic‐stability assessments, phonon analyses, and ab initio molecular dynamics stability at around 300 K. The evaluation of hydrogen storage reveals gravimetric capacities of 1.69 wt.% for TmLiH3 and 1.65 wt.% for YbLiH3, with substantial volumetric capacities of 107 and 107.1 g H2/L, respectively, and suitable desorption temperatures of 381.36 and 336.69 K.
S. Shahrear, Md Saiduzzaman, Md. Al Momin et al.· Advanced Theory and Simulati...· 0 citations
The global movement toward sustainable energy has created growing interest in green hydrogen as a key technology for future energy systems. However, the safe and efficient storage of hydrogen remains a significant challenge. In this study, first-principles calculations were used to examine the phase stability, optoelectronic behavior, and hydrogen storage capability of Al-based metal perovskites XAlH
3
(X = Ga, In, and Tl). The main aim of the research was to assess whether these metal perovskite hydrides could be suitable for solid-state hydrogen storage applications. The calculated formation energies and elastic constants confirm that the XAlH
3
compounds are thermodynamically and mechanically stable. In addition, the positive phonon dispersion results show that all three materials are dynamically stable. The electronic band structure analysis indicates that these hydrides have metallic characteristics. Furthermore, the estimated B/G ratio and Cauchy pressure values suggest that the XAlH
3
materials possess ductile behavior. We also investigated the optical responses of XAlH
3
hydrides in detail. The thermal stability of these hydrides was confirmed by the thermodynamic evaluations and AIMD simulations. The calculated gravimetric hydrogen capacity of GaAlH
3
, InAlH
3
, and TlAlH
3
is found to be 3.03, 2.09, and 1.29 wt%, respectively. Furthermore, the calculated volumetric hydrogen storage capacities for GaAlH
3
, InAlH
3
, and TlAlH
3
are 96.66, 86.63, and 82.43 gH
2
/L, respectively. Desorption temperatures for GaAlH
3
, InAlH
3
, and TlAlH
3
are 397.53 K, 555.64 K, and 218.06 K, respectively. Overall, this study indicates that Al-based perovskite hydrides may be promising materials for solid-state hydrogen storage, and the investigation of XAlH
3
hydrides offers a useful pathway for advancing hydrogen storage technologies.
Abdullah Al Mahmud, Jahirul Islam, S. Aldaghfag et al.· Modern physics letters B· 0 citations
