Theoretical modeling of experimental isotherms for hydrogen storage in La0.9Ce0.1Ni5 alloy

This research reports the results of an experimental and numerical analysis of the La0.9Ce0.1Ni5 alloy's hydrogen absorption and desorption isotherms at three distinct temperatures (T = 313 K, 333 K, and 353 K). We first determined the morphological and structural properties, as well as the hydrogen storage isotherms, of the intermetallic La0.9Ce0.1Ni5 experimentally. The experimental isotherms were then compared to a mathematical model based on statistical physical theory. Due to the good agreement between the experimental isotherms and the proposed model, the insertion and release of hydrogen atoms (n alpha, n beta), geometric densities of receptor sites (N alpha m, N beta m), and absorption-desorption energies (P alpha, P beta) were determined. Moreover, thermodynamic functions like enthalpy, entropy, Gibbs free energy, and internal energy were calculated using these parameters. The findings demonstrated that the intermetallic compound's CaCu5 structure promotes the formation of stable metal hydrides through attractive interactions, ensuring that hydrogen atoms are securely trapped in the metal lattice, thereby enhancing the material's hydrogen storage capacity.