Hydrogen in Metals

Abstract

Metal hydrides are considered a promising means of hydrogen storage mainly because they store hydrogen at low pressure while having volumetric densities comparable to liquid hydrogen (Reilly, 1979). Furthermore, the release of hydrogen in metal hydrides being an endothermic process, this makes them inherently safe. In these lectures, we will discuss how the hydrogen reacts with metals. More specifically, we will see how hydrogen diffuse into the metal and forms a solid solution or a metal hydride. The first lecture treats the basic phenomena of hydrogen-metal systems such as solid solution of hydrogen in metals and formation of metal hydrides with particular emphasis on their structure and thermodynamics. The location of hydrogen in the crystal structure of the host metal will also be reviewed. In the second lecture, the effect of alloying, the electronic structure of metal hydride alloys and kinetics of hydrogen in metals will be studied. In the third lecture, we will see three specific metal hydrides; palladium, niobium and magnesium. Finally, the last lecture will have for object the nanocomposite system Mg-Nb and the possible hydrogen desorption mechanism of this system.