Harnessing the physical attributes of mechanical, structural and dynamical stable alkali-metal perovskite (Rb/Cs)NH6 for sustainable hydrogen storage

Perovskite hydrides are considered potential contenders for hydrogen storage because of their higher energy density. They have the capacity to store a substantial amount of hydrogen by weight and volume, which is critical for energy applications. This study examines the physical properties of (Rb/Cs)NH₆ utilizing the density functional theory. The GGA is exercised to assess the exchange-correlation effects. The studied hydrides structural and thermal integrity is assessed via optimization plots and the formation enthalpies. The obtained elastic constants are positive that signifies the justification of Born's stability criteria. The computed mechanical traits reveal that (Rb/Cs)NH₆ are brittle and possess a higher ability to bear high temperatures. Electronic examination demonstrates that these materials are metallic in origin. Furthermore, an in-depth optical examination shows substantial response in the infra-red region, whereas the absorption coefficient and optical conductivity reveal that (Rb/Cs)NH₆ are highly responsive in the ultraviolet region. The computed gravimetric densities for RbNH₆ and CsNH₆ are obtained as 5.38 wt% and 3.78 wt%, respectively. The hydrogen storage properties signify that these hydrides show immense potential for hydrogen storage purposes and the generation of clean energy, which is align with the United States sustainable development goals.