Hydrogen diffusion in metal-hydrogen systems via NMR and DFT

• NMR study and DFT calculations provide complementary information on hydrogen diffusion in metals.
• To find the activation energy of hydrogen motion in hydrides of Ti–V–Cr alloys 1H NMR relaxation and diffusometry were used.
• KKR-CPA: in fcc hydrides of Ti–V–Cr alloys H atoms are in T-sites and move along <111> axes trough metastable O-sites.
• The calculated hydrogen diffusion coefficient in Mg hcp lattice is in fair agreement with experiment.

Studies of interstitial hydrogen diffusion play a key role in understanding of fundamental properties of hydrogen storage materials since the activation energy required to jump from one interstitial site to another affects both the hydrogen sorption kinetics and the desorption temperature. Nuclear magnetic resonance is a very effective tool to study hydrogen diffusivity, jump frequency etc. but it cannot describe the microscopic hydrogen migration processes. From this perspective theoretical studies are very helpful and complement the experiment, however, the results depend on the quality of calculations. Here we provide a brief overview of our most recent results of both theoretical (DFT) and experimental (1H NMR) studies of hydrides of disordered Ti–V–Cr alloys and a theoretical study of hydrogen diffusion in magnesium.

Figure optionsDownload as PowerPoint slide