We perform first-principles calculations to investigate neutral and charged H vacancies dynamics involving vacancy formation and diffusion in Na 3 AlH6. We find that the activation barrier for local diffusion (diffusion within AlH5 unit) is smaller than that of nonlocal diffusion (diffusion between AlH6 and AlH5 units) for all types of H vacancies; H diffusion in Na3 AlH6 is dominated by mobility of positively charged H vacancies. Furthermore, our results confirm that the observed highly mobile species by anelastic spectroscopy measurements is probably the positively charged H vacancies in the form of local diffusion.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)