The scientists' findings were published in the Materials journal (Q2; IF:3,4).
The metal hydride method of hydrogen storage is considered one of the safest and most efficient. Hydrogen is stored in a chemically bound form, and when it needs to be extracted from the storage device, the metal hydride is heated and the hydrogen is desorbed (released) from the material.
Magnesium hydride is one of the promising materials for use in metal hydride hydrogen storage systems: magnesium is a common, available and inexpensive material that has a high hydrogen storage capacity. At the same time, magnesium hydride is a very stable chemical compound, its decomposition occurs at rather high temperatures (about 400 ºC). This complicates and limits the use of magnesium hydride in the creation of storage materials for hydrogen energy needs.
TPU researchers have developed a new composite with a core-shell type structure based on magnesium hydride that can be used at lower temperatures. For the first time, they used nanoscale aluminum powder obtained by the method of electric explosion of conductors as an additive. In this method, an aluminum wire is placed in a special setup where a high current is passed through it. When the wire explodes, a fine powder is formed, which is then oxidized and a protective oxide film is formed on its surface.
The scientists mixed the resulting nanopowder with magnesium hydride using a planetary ball mill. As a result, a composite was synthesized, which is a specific structure where magnesium hydride acts as the core and nanoaluminum is the shell.
As part of the research, the team studied the morphology and structural phase state of the composite and conducted experiments to determine its desorption characteristics. They showed that the hydrogen yield temperature decreased to 336ºC. The scientists believe that this is due to the addition of aluminum powder and the catalytic effect of the reduction of the activation energy of the hydrogen sorption and desorption processes. In addition, the process of hydrogen release begins at a temperature of about 117 ºC. In the future, the possibilities of using magnesium and aluminum wastes for the production of hydrogen energy will be expanded based on the results obtained.The technology is unique because it allows changing the parameters of the electrical explosion of conductors and, thus, varying the structure and characteristics of the nanopowder itself. In addition, this technology of powder production is used by a number of enterprises, it has been worked out on an industrial scale. This will make it possible to easily and quickly scale up the process of production of storage materials based on magnesium hydride with the addition of metal nanopowders,
Research under the project will continue. Scientists plan to optimize the parameters of nanopowder production and synthesis of the composite itself, which will further reduce the temperature of hydrogen desorption. The researchers also plan to develop experimental hydrogen storage systems based on this composite.