Enhancing hydrogen storage characteristics of novel XV3H8 (X = Ca, Sr, Ba) hydride by A-site cation substitution: Insights from first-principles study

초록

In this study, we conducted a systematic first-principles investigation on the influence of A-site chemistry on the structural and storage properties of V-host XV3H8 hydrides (X = Ca, Sr, Ba) and calculate their physical characteristics. All hydrides are crystallized in a stable cubic phase and demonstrating geometric, dynamical, and thermodynamic stability as evidenced by the absence of imaginary phonon modes and negative formation energies. Ab initio molecular dynamics (AIMD) simulations further confirm their thermal stability, while high Debye and melting temperatures (CaV3H8: 988 K and 1575 K, respectively) indicates thermal robustness. Additionally, optical properties calculation reveals significant response of these hydrides in the ultraviolet and visible regions, characterized by high reflectivity and strong absorption coefficients. Mechanically, the materials exhibit ductile and an anisotropic behavior. The compounds demonstrate exceptional hydrogen storage potential, where CaV3H8 demonstrated the highest gravimetric capacity at 4.01 wt.%, followed by SrV3H8 at 3.24 wt.% and BaV3H8 at 2.70 wt.%. All compounds surpassed the U.S. Department of Energy's (DOE) volumetric targets, which range from 129.90 to 151.58 gH2/L. © 2026 The Physical Society of the Republic of China (Taiwan).

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