Atomistic simulations for electronic structure, mechanical stability and optical responses of sodium-based NaAH3 (A= Sc, Ti and V) metal hydride perovskites for hydrogen storage applications

Hydrogen storage serves a vital role in the advancement of hydrogen-based energy production for commercial use. Solid-state hydrogen storage has garnered significant interest and requires thorough investigation. This study involved the first-principles investigations to explore the phase stability, optoelectronic responses and hydrogen storage potential of Na-based metal perovskites NaAH 3 (A = Sc, Ti, V). The main scope of this study is to evaluate the possible applicability of metal perovskites NaAH 3 (A = Sc, Ti, V) hydrides for solid-state hydrogen storage. Initially, we assess the structural stability of NaAH 3 metal hydrides through calculations of formation enthalpies and phonon dispersion curves . The mechanical stability is assessed through elastic stiffness constants, indicating that NaAH 3 metal hydrides exhibit mechanical stability by satisfying the Born stability criteria. Calculations of the electronic band structure reveal that all NaAH 3 hydrides exhibit metallic properties. Further, we also investigated the optical responses of NaAH 3 hydrides in detail. The gravimetric hydrogen storage capacities of NaScH 3 , NaTiH 3, and NaVH 3 hydrides are 4.09, 3.93, and 3.78 wt%, respectively. Furthermore, we have estimated the volumetric hydrogen storage capacities (C V ) for all NaAH 3 (A = Sc, Ti, V) metal perovskite hydrides. The obtained C V values for NaAH 3 (A = Sc, Ti, V) are 78.99, 95.19, and 110.37 g H 2 l − 1 , respectively, meeting the US-DOE target established for 2025. In short, this study suggests that Na-based perovskite hydrides could serve as effective solid-state hydrogen storage materials . • Na-based metal hydrides have been investigated for solid-state hydrogen storage. • NaAH 3 (A = Sc, Ti, V) hydrides are found to be stable structurally and mechanically. • Highest gravimetric hydrogen storage capacities are determined for NaScH 3 . • NaAH 3 (A = Sc, Ti, V) hydrides are found to be electronically metallic.