TEM-based approach for understanding microstructure-properties relations in hydrogen storing Mg-Ge-Ti and Mg-Ti-Ni nanocomposites

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The lack of an acceptable hydrogen storage media is a critical missing component in allowing for widespread commercial utilization of fuel cells in mobile, hand-held and stationary commercial applications. Magnesium has promise for solid-state hydrogen storage because of the relatively high amount of hydrogen held in MgH2 (7.6wt.%) and because magnesium is inexpensive. The critical problem with magnesium is its unacceptably high charging and discharging temperature due to a relatively large negative heat of hydride formation (-76 kJ/mol). I am proposing to develop alloy Mg-Fe-Ti and Mg-Ti-Ni hydrogen storage nanocomposites. These systems are promising candidates since it may be possible to use the energy of the intermetallics (compounds of two or more elements, where at least one is a metal) formed in their hydrogen-free state to make the heat of formation less negative. I am proposing using alloy thin films as model systems to explore the role of composition and microstructure in the hydrogen storage properties. The alloy design methodology will be accompanied by direct microstructural characterization via cryogenic-stage transmission electron microscopy (TEM). This will give us direct insight into the features of the material necessary for proper adsorption thermodynamics and kinetics.