Dehydriding reaction of AlH₃: In situ microscopic observations combined with thermal and surface analyses

The dehydriding reaction of single-phase α- AlH₃ was investigated by in situ microscopic observations combined with thermal and surface analyses. Before the dehydriding reaction, primary AlH₃ particles of size 100 nm-1 νm were thought to be covered by an oxide layer with a thickness of less than 5 nm. Both the precipitation/grain-growth of metallic Al of size 1-50 nm and an increase in 'boundary space' were clearly observed inside the particles, while the morphologies of the particles covered by the layer did not change during the dehydriding reaction. This preliminary report provides fundamental information for a further study of AlH₃ as a possible hydrogen storage material.