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Titre:	nvestigation of the Electronic and ThermodynamicProperties of Complex Hydrides for Hydrogen Storage
Auteur(s):	AMMI, Hadjer
Mots-clés:	Hydrures de phase Zintl ; Stockage de l'hydrogène ; Anisotropie mécanique ; Stabilité thermique ; Modèle quasi-harmonique ;, Modèle de Debye ; Réseau hexagonal ; Capacités de stockage de l'hydrogène
Date de publication:	2025
Editeur:	Université de BOUIRA جامعة البويرة
Référence bibliographique:	This dissertation presents a comprehensive computational investigation of the structural, electronic, mechanical, and thermodynamic properties of Zintl-phase hydrides XMSiH (X = Sr, Ca, Ba; M = Al, Ga) using Density Functional Theory (DFT) within the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) framework. All compounds stabilize in a hexagonal structure (space group P3m1) featuring a distinctive layered configuration of M–Si and X–H layers that facilitates efficient hydrogen diffusion. Electronic structure analysis reveals semiconducting behavior with indirect band gaps ranging from 0.6 to 1.2 eV, tunable through composition and exchange-correlation functionals (GGA, LDA, mBJ-GGA, mBJLDA). The study identifies promising hydrogen storage characteristics, with gravimetric capacities reaching 1.05 wt% for CaAlSiH and desorption temperatures varying from 311.57 K to 748.90 K across the series. Thermodynamic properties evaluated via the quasi-harmonic Debye model demonstrate stability across wide pressure (0-40 GPa) and temperature (0-1000 K) ranges. Mechanical analysis confirms elastic stability with significant anisotropy in the {100} plane, while bulk modulus values indicate enhanced compressibility compared to conventional metallic hydrides. The ordered hexagonal arrangement of Ga, Al, and Si atoms is shown to optimize hydrogen retention and cycling performance. These findings collectively establish XMSiH hydrides as compelling candidates for next-generation solid-state hydrogen storage, offering an optimal combination of structural integrity, tunable electronic properties, and functional performance for renewable energy applications.
URI/URL:	http://dspace.univ-bouira.dz:8080/jspui/handle/123456789/19198
Collection(s) :	Faculté des Sciences et des Sciences Appliquées

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