Density functional study of barium and strontium boron hydrides for hydrogen storage and optoelectronic applications

The structural, electronic, optical, mechanical, magnetic, thermal, and hydrogen storage properties of boron-based hydrides XBH₃(X = Ba, Sr) are investigated in this work through DFT calculations using the WIEN2K Simulation Package. Their potential for H₂ storage is highlighted, underscoring their importance for energy storage applications. The studied boron-based hydrides, XBH₃ (X = Ba and Sr), crystallize in a cubic phase, according to structural optimizations. For BaBH₃ and SrBH₃, the calculated lattice constants are 3.71 Å and 3.52 Å, respectively. These compounds are metallic, according to the analysis of their electronic properties. The Pugh index and Cauchy pressure confirmed the brittleness of both hydrides. A thorough examination of the formation energy, elastic characteristics, and phonon dispersion curves has verified that these materials are thermodynamically, mechanically, and dynamically stable. These materials have high dielectric functions in the visible spectrum, according to the optical properties of XBH₃ (X = Ba, Sr). The absorption spectra, on the other hand, show a noticeable peak in the ultraviolet region. The heat capacity curves of these hydrides indicate their capacity to conduct thermal energy effectively. XBH₃ (X = Ba, Sr) shows encouraging hydrogen storage capacities of 1.96 weight% and 2.89 weight%, respectively, according to gravimetric analysis. These findings demonstrate the perovskite hydrides' significant potential for application in hydrogen storage systems and optoelectronics applications.