DFT Investigation of the Thermoelectric, Electronic, and Hydrogen Storage Properties of MgMH3 (M = Mn and Ni) Perovskites Using BoltzTrap

Abstract

This study provides a theoretical assessment of the structural, electronic, and thermal properties of MgMH3 (M = Mn and Ni) compounds using the full-potential linearized augmented plane wave (FP-LAPW) method, with a range of modern functionals. The thermoelectric properties that are surveyed here relate to the power factor, the dimensionless thermoelectric figure of merit, the thermal conductivity, and the electrical conductivity that are associated with these compounds. The study finds that MgNiH3 has superior thermoelectric properties compared to MgMnH3. The analysis of the band structure reveals that both materials conduct electricity like metals, as there is no energy gap (0 eV), indicating that the conduction and valence bands overlap. The thermal conductivity was found to be linearly related to an increase in temperature, whereas the electrical conductivity varied with temperature. At elevated temperatures, the maximum power factor values reach 1.45 × 10−3 W/(K2.m) for MgMnH3 and 1.96 × 10−3 W/(K2.m) for MgNiH3 at 900 K. Upon examination of the electronic states, the contributions to the metallic nature of these hydrides come largely from the Ni and Mn orbitals. This type of prospective information on the potential of MgNiH3 and MgMnH3 in industrial applications, especially thermoelectric applications, is a valuable contribution. Understanding their thermal and electronic structure will demonstrate their potential for industry.