Atomic and electronic structure of hydrogen-related centers in hydrogen storage materials

Hydrogen-related point defects play an important role in the (de)hydrogenation kinetics of hydrogen storage materials. First-principles calculations have been performed for hydrogen vacancies and hydrogen interstitials in NaAlH4. The results show that all of the relevant point defects are charged, and hence their formation energies and concentrations are strongly Fermi-level dependent. Several of the point defects induce significant rearrangements of the surrounding lattice. The electronic structure of the induced defect states is examined.