This study explores the solid-state hydrogen storage capacity of A
2
SnH
6
(A = Li, Na, K) double perovskite hydrides. The substitution of Li with Na and K leads to an increase in lattice parameters from 7.56 to 7.73 and 7.99 Å. The enthalpy of formation and AIMD computation confirm their thermodynamic and thermal stabilities. The gravimetric hydrogen storage capacities decrease from 4.36 wt% (Li
2
SnH
6
) to 3.54 wt% (Na
2
SnH
6
) to 2.97 wt% (K
2
SnH
6
). All these configurations have wide indirect band gaps (2.74–3.12 eV), demonstrating their semiconducting nature, making them viable for UV photocatalytic water splitting. The calculated values of Pugh B
0
/G are Li
2
SnH
6
= 4.31, Na
2
SnH
6
= 2.59, and K
2
SnH
6
= 1.94, confirming their ductile nature. Furthermore, Na
2
SnH
6
exhibits the highest thermoelectric figure of merit (ZT = 0.79). While Li
2
SnH
6
provides the highest gravimetric hydrogen capacity, Na
2
SnH
6
exhibits the lowest predicted desorption temperature (311.07 K), compared with 337.36 K for K
2
SnH
6
. Overall, Na
2
SnH
6
emerges as the most promising candidate for meeting the U.S. DOE hydrogen storage targets.
Usman Saeed, Ghulam M. Mustafa, N. A. Noor 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
