A first-principles study of pressure-induced changes in the physical properties and hydrogen storage capacities of alkali beryllium hydrides ABeH3 (A = Na, K) for green energy applications

초록

Hydrogen is emerging as a viable and sustainable energy source because of its vast supply, high energy density, potential for clean production, and zero emissions. While metal hydrides remain the dominant class of solid-state hydrogen storage materials, recent research has explored perovskite-type hydrides as complementary alternatives due to their lightweight nature, high gravimetric hydrogen storage capacity, and tunable structural properties, making them attractive for specific applications where weight constraints are critical. The structural, electronic, optical, elastic, mechanical, and thermodynamic properties of Alkali beryllium hydrides ABeH3 (A = Na, K) are investigated computationally in this work using the CASTEP tool. The aforementioned characteristics are calculated using Approximation GGA-PBE. Under the influence of 0, 25, and 50 GPa pressures, the crystalline structure of ABeH3 (A = Na, K) compounds exhibits a stable cubic shape. Furthermore, the electronic investigation verifies the semiconductor nature of ABeH3 (A = Na, K). The mechanical and dynamic stability of these perovskite-type hydrides is determined using born stability criteria and phonon dispersion analysis. These compounds NaBeH3 and KBeH3 also have greater gravimetric ratios, 8.63 and 5.91 wt%, respectively, making them appropriate for long-term hydrogen fuel storage.

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