Computer-Aided Design of Laves-Phase Alloys for Hydrogen Storage

• Applicant: Dr. Yuji Ikeda
• Subject Area: Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 519607530

In the present project proposal, we aim to discover new hydrogen-storage alloys—that can be activated at room temperature—from the vast compositional space of high-entropy alloys (HEAs) in Laves phases. For this purpose, we will establish a methodological framework to design hydrogen-storage alloys based on ab initio density functional theory (DFT) calculations and Monte Carlo simulations addressing both the thermodynamics and kinetics. We will first obtain comprehensive data for fundamental properties of hydrogen absorption and diffusion, e.g., binding and activation energies of H atoms at dilute H concentrations, in the Lave-phase alloys based on ab initio DFT simulations. We start from ordered Laves-phase alloys with taking care of all the symmetrically inequivalent interstitial sites potentially available for H atoms and then extend this approach to the HEAs in Laves phases with carefully analyzing the dependence of H energetics on the local chemical environment around the interstitial sites. The second step is to develop a framework to investigate the absorption and the diffusion of H atoms at more realistic finite H concentrations based on the computed ab initio data. Metropolis Monte Carlo (MMC) simulations will be used in combination with the cluster-expansion (CE) Hamiltonian to compute the equilibrium H concentration, i.e., the H capacity, as a function of temperature and pressure. Kinetic Monte Carlo (KMC) simulations will be employed to compute H diffusion coefficients. The thus developed framework will be finally used to scan the vast compositional space of the HEAs in Laves phases to discover new compositions showing favorable properties for hydrogen storage. We particularly aim at hydrogen-storage alloys that can absorb and desorb hydrogen at moderate temperature and pressure and do not require complicated activation processes. Under these constraints, we will optimize the compositions to get a high H capacity and a high H absorption rate. The thus designed alloys will be synthesized in cooperation with experimental partners, and the actual properties for hydrogen storage will be evaluated. The data obtained within the project will be made public in an established manner. The results and the knowledge gained in the project should largely accelerate the development of hydrogen technologies such as fuel cells and contribute to reduce the consumption of fossil fuels.

• DFG Programme: Research Grants
• International Connection: Japan
• Cooperation Partner: Professor Kaveh Edalati