First-principles investigation of BX3H9 (X = Ca, Sc, Ti) hydrides: Structural, electronic, phonon, and hydrogen storage properties

Abstract

Hydrogen storage materials are essential for sustainable energy applications. This study investigates the structural, electronic, elastic, phonon, and hydrogen storage properties of BX₃H₉ (X = Ca, Sc, Ti) using first-principles calculations based on density functional theory (DFT). Phonon dispersion confirms the dynamical stability of these hydrides. The gravimetric hydrogen storage capacity (Cwt%) exceeds 5.5 wt% for all compounds, meeting U.S. Department of Energy (DOE) standards. Among them, BTi₃H₉ exhibits the lowest desorption temperature, making it highly promising for hydrogen release under mild conditions. Elastic properties validate the mechanical stability, while electronic structure analysis provides insight into bonding characteristics. These results highlight the potential of BX₃H₉ compounds as effective hydrogen storage materials. Our findings contribute to the advancement of lightweight metal hydrides, offering a foundation for the development of next-generation hydrogen storage technologies.