Invited Paper EN+SE+NS+SS-MoA7
Atomistic Mechanisms of Reversible Hydrogen Storage in Complex Metal Hydrides
Monday, October 20, 2008, 4:00 pm, Room 203
The storage of hydrogen in a lightweight, high-capacity medium with fast charge/discharge kinetics has been recognized as one of the primary challenges in achieving the transition to a hydrogen-based economy. Hydrogen-rich compounds, such as complex metal hydrides, offer potentially high storage capacities but the solid-state hydrogen storage reactions in these materials generally proceed slowly and in many instances are not reversible, i.e., re-hydrogenation of the depleted products cannot be realized by controlling temperature and hydrogen pressure alone. The use of doping to achieve reversibility and fast reaction kinetics has been demonstrated successfully for a particular complex metal hydride, sodium alanate (NaAlH4). Here we discuss our recent efforts on identifying the atomic-scale effects of such doping by microscopy and spectroscopy experiments on well-defined model systems (e.g., single crystal surfaces), closely linked to ab-initio theory and simulations. A comprehensive understanding of important microscopic reaction mechanisms allows deriving general guidelines for the use of dopants or catalysts to accelerate hydrogen storage reactions in alanates, and possibly in a broader class of solid-state storage materials.