Novel Perovskite Hydrides Show Promise for Hydrogen Storage – DFT Study

A recent study in the International Journal of Hydrogen Energy led by Muhammad Awais Rehman explored new perovskite hydrides for storing hydrogen, using a method called density functional theory (DFT) calculations.

The study, titled “Exploring the Hydrogen Storage in Novel Perovskite Hydrides: A DFT Study,” examined the structure, hydrogen storage ability, mechanical, electronic, optical, and bonding properties of the compounds KNaX2H6, where X is either magnesium (Mg) or calcium (Ca).

The research found that the perovskite hydrides KNaMg2H6 and KNaCa2H6 are both stable in terms of their mechanical and thermodynamic properties. These compounds showed significant potential for hydrogen storage, with a capacity of 5.19% for KNaMg2H6 and 4.09% for KNaCa2H6. They also behave as semiconductors with indirect energy band gaps of 3.31 eV and 3.17 eV, respectively.

The stability of these hydrides was confirmed by using negative formation energies, positive phonon dispersions, and appropriate tolerance factors. Mechanical properties like bulk modulus, shear modulus, and Poisson’s ratio were determined using elastic constants. The desorption temperature for KNaMg2H6 was found to be 470.4 K, indicating its practical use. Bonding analysis showed a mix of ionic and slightly covalent interactions. Additionally, these materials showed strong ultraviolet light absorption with a shift in the absorption spectrum.

The study suggests that KNaMg2H6, with its higher hydrogen storage capacity and suitable desorption temperature, could be very useful in hydrogen fuel cell vehicles and portable hydrogen storage systems. This research is a key step toward developing better hydrogen storage materials, helping to reduce the reliance on fossil fuels and lessen environmental impacts.