Studies of Metal-Hydrogen Reaction Mechanisms in Multicomponent Alloys for Solid-State Hydrogen Storage: Applications of in-situ X-ray Diffraction

Abstract

This PhD research project involves the characterization of the metal-hydrogen reaction mechanisms during the hydrogen absorption and desorption processes in new multicomponent alloys, for applications such as a metal hydride. The knowledge of the reversibility and stability of the phases during the processes of hydrogen absorption and desorption will allow us to advance more significantly in the design of the alloy/system, above all, to judge whether a given composition presents the necessary conditions for a possible application. Therefore, it is necessary to develop devices capable of studying the in-situ behavior of new materials under hydrogen exposure. Therefore, this research project intends to develop two types of sample holders: i) a "capillary cell" type sample holder, ii) a "dome type" sample holder, which can be pressurized from the connection in an apparatus of the Sieverts type. This Sieverts-type apparatus allows different "sample holder" designs containing study samples to be pressurized in incremental doses at the desired temperature at hydrogen pressures. Therefore, this research will seek to understand the differences and possible similarities between the structures present in multicomponent alloys under different stages of hydrogen absorption, identify the mechanisms and transformations of phases acting in multicomponent alloys and, in this way, optimize alloys with better hydrogen storage properties.