H storage in solid materials


Nowadays, the global warming is unequivocal, thus requiring novel groundbreaking technologies for limiting the emissions of greenhouse gases. Hydrogen is a promising and sustainable candidate. Indeed, it is one of the most abundant elements on Earth, so that it pioneers the next technological revolution by propelling the new vehicle generation. As a case in point, 24 kg of gasoline are required for a modern combustion-engine car to travel 400 km, whereas the same distance can be covered using only 8 kg of hydrogen. Moreover, the engine only rejects water vapor. Therefore, intense research aims to improve hydrogen storage in order to face the challenge of the global warming.

Volume of 4 kg of hydrogen compacted in different ways, with size relative to the size of a car (Sflapbach et al. Nature, 2001).

However, the use hydrogen remains very challenging because it needs to be stored onboard safely and compactly at room temperature. Indeed, nobody forgets the terrible crash, in 1937, of the Zippelin-Hindenburg. The first approach, already used in the current hydrogen vehicles, is to store the hydrogen in its gas or liquid state. Such methods require extremely pricey tanks resisting to both high pressure and specific very low temperature container in order to limit the constant evaporation. Therefore, these solutions are definitively not compatible with our daily life and safety requirements.

A promising route for hydrogen storage is possible. It consists in storing it within solid materials using reversible metastable hydrides in order to enable absorption/desorption mechanisms. Using this type of container will remove all the limitations imposed by pressurized tank and they will drastically reduce the weight of the vehicle. However, there is a poor understanding of the effects of structural defects and catalysts on the physical mechanisms of the reaction because of numerous constraints.

Ongoing project on the H storage

2020–2023: Thesis of Adrien HEINZELMEIER
Absorption/desorption of hydrogen in MAX phases, MXenes and their Mg-based nanocomposites.