Etudiant : ZEROUAL MADIHA

Filière : Master Matériaux et Applications pour l’Energie Photovoltaïque (MAEP)

Encadrant : Pr. AHFIR RACHID

Annèe : 2024

Résumé : Density functional theory (DFT) has been used to perform an ab initio study of novel NaWH3 hydrogen storage materials using the generalized gradient approximation (GGA) and the CASTEP software package. The structural, electronic, plastic, optical and hydrogen storage properties of NaWH3 were calculated in the cubic perovskite phase Pm3̄m. The thermodynamic stability of the structure was ensured by the negative enthalpy of formation. Calculations of the elastic constants confirm the mechanical stability of this material. In addition, the compressibility modulus, shear modulus and Poisson's ratio were calculated using the elastic constants obtained. NaWH3 hydride was found to be elastically anisotropic and brittle. Electronic band structures show metallic behavior in NaWH3 perovskite. Optical characteristics show that this compound exhibits the highest levels of absorption and conductivity in the ultraviolet and red wavelength range. Gravimetric calculations of the hydrogen storage capacity for NaWH3 were carried out and gave a value of ≈1.402 wt%. The hydrogen desorption temperature was identified as 367 K for NaWH3. The current DFT results emphasize that the hydride NaWH3 has considerable potential as a candidate for H2 storage