Thickness effects on electrochemical and gas-phase hydrogen loading in magnesium thin films

Renewable hydrogen is one of the tools necessary to reduce carbon emissions and achieve climate neutrality by 2050, so its production and consumption is planned to increase in the following 30 years. Developing new techniques for hydrogen storage is thus extremely relevant at the moment. Magnesium is a good candidate for hydrogen storage in solids due to its light weight, abundance, safety of operation and high achievable hydrogen density. However, the Magnesium-Hydrogen system needs to be investigated and understood more deeply. This work focuses on the behaviour of hydrogen in magnesium thin films, using the techniques of electrochemical loading in KOH and gas-phase loading. The formation of magnesium hydride was studied by measuring and comparing isotherm curves. With electrochemical loading it was possible to observe different behaviours during magnesium hydride formation, related to the intensity of the applied driving force. Both hydrogen loading techniques allowed to observe effects related to the thickness of the Magnesium layer. In particular, the voltage or pressure at which Magnesium hydride is formed increases as the film gets thinner.