Numerical and experimental analysis of hydrogen absorption on Lanthanum pentanickel

Hydrogen storage in metal hydrides offers a promising solution for safe and efficient energy systems, yet accurate reactor-scale modeling remains computationally demanding due to the strong coupling between heat transfer, mass transport, and reaction kinetics. This work presents the development of a closed and consistent numerical model for hydrogen absorption within the Extended Discrete Element Method (XDEM) framework, designed to balance computational efficiency and predictive accuracy for particle-scale simulations. The model describes the complexity of particle-level thermochemical interactions through a heterogeneous equilibrium formulation derived from the pressure-composition-temperature diagram based on physical principles while retaining essential physical fidelity, including the effects of heat generation, spatial and temporary gradients. Validation against detailed XDEM simulations and experimental data demonstrates that the approach reproduces key transient behaviors of the absorption process with minimal loss of accuracy. The resulting model significantly reduces computational cost, making it suitable for integration into multi-physics reactor models involving thermal management and flow interactions. Hence, this work establishes a foundation for efficient large-scale simulations of hydrogen storage systems using XDEM. • Physically based representation of PCT diagram by adsorption isotherms. • absorption of hydrogen described through a heterogeneous equilibrium based on XDEM. • Representation of the PCT characteristics dependent on temperature and pressure. • Accurate representation of the dynamic system of absorption.