Magnesium hydride (MgH2), a binary inorganic compound with a hydrogen concentration of 7.66%, is a form of H2 storage. However, hydrogen desorption from MgH2 only occurs at a temperature of more than 400 degrees Celsius, which makes it harder to use for the needs of the hydrogen energy industry. The scientists from Tomsk Polytechnic University have attempted to reduce the desorption temperature by creating a new composite material, in which nano-sized aluminum powder was used as an additive to magnesium hydride.
To obtain this powder, the scientists placed a metal wire in a special unit, through which a metal current was passed. After the wire exploded, a fine powder was formed, the oxidation of which led to the formation of a protective oxide film on its surface. The scientists mixed the resulting nanopowder with magnesium hydride using a planetary ball mill, i.e., a device for fine and ultrafine grinding of materials. As a result, the authors synthesised a composite, in which magnesium hydride is the core and nanoaluminum is the shell.
“The technology is unique in that it allows us to change the parameters of the electrical explosion of conductors, thereby changing the structure and characteristics of the nanopowder itself. Plus, this technology for producing powders is used by a number of enterprises: it has been developed on an industrial scale. This will make it possible to easily and quickly scale up the production of storage materials based on magnesium hydride with the addition of metal nanopowders,” Viktor Kudiyarov, associate professor at the Division for Experimental Physics, is quoted as saying by Tomsk Polytechnic University.
Experiments with the new composite showed partial hydrogen desorption occurring at a temperature as low as 117 degrees Celsius, and complete desorption taking place at 336 degrees Celsius. These results could make it easier to create magnesium hydride-based hydrogen storage systems.