First-principles investigation for the hydrogen storage properties of AeSiH3 (Ae = Li, K, Na, Mg) perovskite-type hydrides

Abstract

The present study investigates the physical properties of AeSiH3 (Ae = Li, K, Na, Mg) hydrides perovskites with their hydrogen storage capability. All the materials are thermally, dynamically, and mechanically stable. The lattice constants are 4.001, 3.917, 3.986, and 3.977 Å for LiSiH3, KSiH3, NaSiH3, and MgSiH3, respectively. The gravimetric ratio for hydrogen storage capacity is 7.946, 4.306, 5.588, and 5.456 wt% for LiSiH3, KSiH3, NaSiH3, and MgSiH3, respectively. All the materials have zero bandgap and possess a brittle nature with ionic bonding. Elastic constants were used to determine the mechanical properties like bulk modulus, shear modulus, Young's modulus, and Poisson's ratio. The thermodynamic parameters such as Debye temperature and melting temperature are also calculated and discussed in detail using the elastic constants. These calculated properties suggest that AeSiH3 (Ae = Li, K, Na, Mg) hydride perovskites are potential candidates for hydrogen storage applications.