Computational evaluation of novel XCuH3 (X = Li, Na and K) perovskite-type hydrides for hydrogen storage applications using LDA and GGA approach

Hydrogen energy has attracted a lot of interest from researchers as a sustainable and renewable energy source, but there are some technical challenges related to its storage. Hydride materials demonstrate the ability to store hydrogen adequately and safely. In the current study, we have investigated the structural and optoelectronic properties of the XCuH₃ (where X = Li, Na and K) perovskite-type hydride using LDA and GGA formalisms for hydrogen storage application. Electronic properties such as band structure, density of states reveal the metallic character of the studied XCuH₃ hydrides. Various optical parameters such as the complex dielectric function, refractive index, extinction coefficient, absorption coefficient, reflectivity, optical conductivity, energy loss function, and joint density of states have been computed and compared. The gravimetric hydrogen storage capacity for LiCuH₃, NaCuH₃ and KCuH₃ are found to be 4.11, 3.37 and 2.86 wt%, respectively. The computed values of the gravimetric ratio manifest that XCuH₃ hydrides are potential candidates for hydrogen storage applications. These calculations are made for the first time for XCuH₃ hydrides and will be inspirational in the future for comparison and for hydrogen storage purposes.