An extensive study of structural, electronic, elastic, mechanical and optical properties of XCdH3 (X=K, Rb) for hydrogen storage applications: First-principles approach

The energy crisis can be met by switching to renewable energy sources. The present study explores the physical and hydrogen storage capacity of XCdH3 (X = K, Rb) by first-principles study. According to the phonon spectrum and formation, energy materials are dynamically stable. The electronic profile revealed that the concerned compounds are half-metallic. Furthermore, the electronic band gap is evaluated in terms of the total and partial density of states. In terms of hypothetical dielectric function optical properties are discussed and in the energy range of 0–40 eV. In optical properties, the highest reflectivity and absorption are observed in KCdH3. Mechanically, KCdH3 shows brittle properties and RbCdH3 has ductile properties. Lattice constant, elastic coefficient, Poisson ratio anisotropy, Young, and shear modulus, are calculated. The gravimetric hydrogen storage is found 5.55 %, and 4.32 % wt% of KCdH3 and RbCdH3, respectively. KCdH3 qualified as the best substance for storing hydrogen due to the greater gravimetric ratio. All the above parameters are calculated the first time. Evaluation of concerned material provides a roadmap and significant contribution to scientific literature for future prospective.