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

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.