Activating aluminium for oxidation and hydrogen release: Overcoming the passivation barrier with superheated steam

Aluminium has considerable potential for use in seasonal energy storage, as it is energy dense and stable and can be recycled sustainably. However, a dense alumina barrier prevents energy extraction. In this work, aluminium is activated, and energy is extracted by oxidation using pressurized superheated steam. The activation of aluminium by penetrating the dense passivation layer requires the right feed material and reaction conditions. The onset mechanism is studied for low-yield reactions up to 2 %. In combination with pressures above 10 barG, microcracks form at temperatures above 500 °C. The diffusion of superheated steam through microcracks into the core of the aluminium results in oxidation past the passivation barrier and the evolution of H 2 . This concept is further proven by the detection of Al 2 O 3 . This alternative reaction route in a dry oxidizing environment broadens the application range of aluminium as a metal fuel for long-term chemical energy storage. • Oxidation of bulk aluminium using superheated steam. • Determination of reaction parameters for the onset of the oxidation reaction. • Characterization of the pathway for interaction between steam and aluminium.