Hydrogen storage potential of perovskite hydrides: Ab-initio investigations and prospects for clean hydrogen energy

Hydrogen shows great potential as a clean and sustainable energy solution to tackle the energy problem, as well as the environmental and health hazards associated with existing energy sources. Metal hydrides have shown considerable promise in the field of hydrogen storage. The perovskite hydrides SrAH3 (A = K, Li, Na) exhibit promising hydrogen storage capabilities, with SrKH3, SrLiH3, and SrNaH3 achieving outstanding gravimetric hydrogen densities of 2.33, 3.10, and 2.66 wt%, respectively. The computed electronic characteristics demonstrate that SrAH3 (A = K, Li, Na) perovskite hydrides are indirect bandgap semiconductor materials. The calculated values of energy bandgaps for SrKH3, SrLiH3, and SrNaH3 are 3.29, 2.54, and 2.65 eV, respectively. Based on ground state energy (E0), SrKH3 is the most stable compound among SrAH3 (A = K, Li, Na). The SrAH3 (A = K, Li, Na) molecules primarily absorb energy quanta within the visible region, but they also demonstrate significant absorption in the ultraviolet (UV) region. Moreover, it has been confirmed that these perovskite hydrides possess thermodynamic stability, as shown by their presented thermodynamic characteristics. These compounds can be inferred as potential candidates for thermoelectric device applications as they have fair values of the figure of merit (ZT).