Exploring BaMg2XH8 (X = V, Mn, Fe, and Co) hydrides for solid-state hydrogen storage: Mechanical, electronic, optical, and phonon perspectives
- 1Laboratory of Advanced Materials and Applications (LM2A), Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez-Atlas, Morocco
- 2Laboratory of Analytical and Molecular Chemistry, Faculty of Sciences Ben M’Scik, Hassan II, University of Casablanca, Casablanca, Morocco
Abstract
The development of safe, efficient solid-state hydrogen storage media remains a critical hindrance in the transition to a hydrogen economy. In this study, we employed Density Functional Theory (DFT) with a Hubbard U correction to systematically investigate the structural, mechanical, electronic, and optical properties of the complex metal hydrides BaMg 2 XH 8 (X = V, Mn, Fe, and Co). Structural optimization reveals that these hydrides crystallize in a trigonal P 3 ¯ m 1 space group, exhibiting thermodynamic stability consistent with their negative formation energies. Mechanical assessment confirms that all variants satisfy the Born stability criteria, displaying a brittle nature. Electronic structure analysis distinguishes BaMg 2 VH 8 , BaMg 2 MnH 8 , and BaMg 2 FeH 8 as semiconductors with band gaps of 1.931, 1.606, and 2.364 eV, respectively, whereas BaMg 2 CoH 8 exhibits metallic character. Crucially, phonon dispersion analysis highlights a divergence in dynamic stability; while the Fe- and Co-based hydrides are dynamically stable, the V- and Mn-based analogues exhibit imaginary vibrational modes, indicating intrinsic instability at 0 K. Consequently, we identify BaMg 2 FeH 8 and BaMg 2 CoH 8 as the primary viable candidates for experimental synthesis, offering gravimetric capacities of 3.22 wt% and 3.18 wt%, respectively, alongside promising volumetric hydrogen densities of 110.0 and 108.8 kg H 2 /m 3 . Furthermore, the strong ultraviolet absorption and optical conductivity observed in these stable compounds suggest their potential for photo-enhanced hydrogen desorption, making them promising candidates for stationary storage systems integrated with solar-thermal management technologies.
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BibTeX
@article{akarchaou2026exploring,
title = {{Exploring BaMg2XH8 (X = V, Mn, Fe, and Co) hydrides for solid-state hydrogen storage: Mechanical, electronic, optical, and phonon perspectives}},
author = {El Houcine Akarchaou and Mohammed Hadhoud and Oumayma Eddahmani and Abdelghafour El Mekkaouy and Samir Chtita and Rodouan Touti},
journal = {Journal of Magnesium and Alloys},
year = {2026},
month = may,
doi = {10.1016/j.jma.2026.102093},
url = {https://doi.org/10.1016/j.jma.2026.102093},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Exploring BaMg2XH8 (X = V, Mn, Fe, and Co) hydrides for solid-state hydrogen storage: Mechanical, electronic, optical, and phonon perspectives
AU - El Houcine Akarchaou
AU - Mohammed Hadhoud
AU - Oumayma Eddahmani
AU - Abdelghafour El Mekkaouy
AU - Samir Chtita
AU - Rodouan Touti
PY - 2026
DA - 2026/05/15
JO - Journal of Magnesium and Alloys
DO - 10.1016/j.jma.2026.102093
UR - https://doi.org/10.1016/j.jma.2026.102093
AB - The development of safe, efficient solid-state hydrogen storage media remains a critical hindrance in the transition to a hydrogen economy. In this study, we employed Density Functional Theory (DFT) with a Hubbard U correction to systematically investigate the structural, mechanical, electronic, and optical properties of the complex metal hydrides BaMg 2 XH 8 (X = V, Mn, Fe, and Co). Structural optimization reveals that these hydrides crystallize in a trigonal P 3 ¯ m 1 space group, exhibiting thermodynamic stability consistent with their negative formation energies. Mechanical assessment confirms that all variants satisfy the Born stability criteria, displaying a brittle nature. Electronic structure analysis distinguishes BaMg 2 VH 8 , BaMg 2 MnH 8 , and BaMg 2 FeH 8 as semiconductors with band gaps of 1.931, 1.606, and 2.364 eV, respectively, whereas BaMg 2 CoH 8 exhibits metallic character. Crucially, phonon dispersion analysis highlights a divergence in dynamic stability; while the Fe- and Co-based hydrides are dynamically stable, the V- and Mn-based analogues exhibit imaginary vibrational modes, indicating intrinsic instability at 0 K. Consequently, we identify BaMg 2 FeH 8 and BaMg 2 CoH 8 as the primary viable candidates for experimental synthesis, offering gravimetric capacities of 3.22 wt% and 3.18 wt%, respectively, alongside promising volumetric hydrogen densities of 110.0 and 108.8 kg H 2 /m 3 . Furthermore, the strong ultraviolet absorption and optical conductivity observed in these stable compounds suggest their potential for photo-enhanced hydrogen desorption, making them promising candidates for stationary storage systems integrated with solar-thermal management technologies.
SN - 2213-9567
ER -