Fabrication of AlLi and Al2Li3/Al4Li9 intermetallic compounds by molten salt electrolysis and their application for hydrogen generation from water

The concept of “hydrogen on demand” has been widely publicized. More importantly, the materials used to produce hydrogen on demand should be in themselves safe to handle. In present work, Al–Li intermetallic compounds (IMC) were fabricated in air by electrolysis from LiCl–KCl molten salt at 480 ± 25 °C. Bulk AlLi IMC and the bulk compound with mixture of Al2Li3 and Al4Li9 (Al2Li3/Al4Li9 IMC) were not pyrophoric and can be safely handled in air. When both compounds in contact with water, vigorous reaction occurred and H2 was directly produced. The by-products after H2 generation from AlLi IMC were a mixture of Li-containing α-Al and Li–Al hydrotalcite (hereafter referred to as Li–Al LDH). The by-product after H2 generation from Al2Li3/Al4Li9 compound was a mixture of LiOH·H2O and Li–Al LDH. Those by-products can be easily separated from water and may be reused as a resource. Approximately 500–860 ml of H2 per weight (g) of the IMC compounds was generated in deionized water at room temperature. Experimentally, AlLi IMC powder and Al2Li3/Al4Li9 compound exhibit gravimetric hydrogen capacity of 7.0 wt.% and 5.4 wt.%, respectively. Although the energy consumed for fabricating Al–Li IMC compounds is a little larger than the energy provided by the generated H2, the Al–Li IMC compounds are promising materials for producing hydrogen on demand without the necessity of hydrogen storage.

► AlLi and Al2Li3/Al4Li9 compounds vigorously reacted with water to generate hydrogen. ► Al–Li IMC could exhibit gravimetric hydrogen capacity of 5.4–7.0 wt.%. ► No catalyst was used in the hydrogen generation reaction. ► The Al–Li intermetallic compounds could be prepared in air.