In this study, density functional theory (DFT) is utilized to explore the structural, electronic, optical, mechanical, thermodynamic, and hydrogen storage properties of MCa Mʹ H6 (M =Li, Na; Mʹ =Co, Rh, Ir) double perovskite- type hydrides for the first time. The structural analysis confirms that all the studied materials crystallize in the cubic phase with space group 216 (F 43 m). The phonon dispersion analysis confirms that five hydrides LiCaRhH6, LiCaIrH6, NaCaCoH6, NaCaRhH6, and NaCaIrH6 demonstrate dynamic stability, while LiCaCoH6 shows the presence of soft modes. Furthermore, ab initio molecular dynamic (AIMD) simulations confirmed the thermal stability of the studied materials, showing no structural deformation. All compounds exhibit indirect bandgap semiconductor behavior based on their electronic properties, while a reduction in bandgap is observed when the cationic atom at the M and Mʹ-site in MCa Mʹ H6 is substituted. The mechanical properties findings reveal that all the hydrides are mechanically stable and exhibit brittle behavior. We employed the Quasi- Harmonic Debye model to analyze the thermodynamic behavior across different temperatures, and the results align well with fundamental thermodynamic principles. The hydrogen storage characteristics reveal that the studied materials LiCaCoH6, LiCaRhH6, LiCaIrH6, NaCaCoH6, NaCaRhH6, and NaCaIrH6 exhibit storage capac ities of 5.40, 3.38, 2.47, 4.72, 3.52, and 2.31 wt%, respectively, demonstrating their potential suitability for hydrogen storage applications. Our findings reveal that LiCaCoH6 is the most suitable material for H2 storage, as it not only demonstrates the highest storage capacity within the proposed materials but also surpasses the target values established through the US Department of Energy (DOE).

العنوان

Surfaces and Interfaces

الناشر

ELSEVIER

بلد الناشر

البرازيل

Indexing

Thomson Reuters

معامل التأثير

6,2

نوع المنشور

Both (Printed and Online)

المجلد

36

السنة

2025

الصفحات

10