Scientists have designed a simple and direct method for the synthesis of a solid-state hydrogen storage material, alane (AlH3). Alane, one of the forefront materials for practical solid-state hydrogen storage, has a hydrogen capacity of 10% by weight and gives up hydrogen in a single step at the temperature that is close to the operating temperature of hydrogen fuel cells. Prior to this work, realizing the enormous potential of alane has been frustrated by the lack of a straightforward method for its synthesis. The one-step synthesis takes under an hour and can be performed without solvents. Under hydrogen, helium, or argon pressure, three parts lithium aluminum hydride (LiAlH4) and one part aluminum chloride (AlCl3) are mixed in a miniature version of a clothes dryer for 30-60 minutes with ball bearings. Ball milling above a critical pressure seems key to completely suppressing the unwanted formation of metallic aluminum. This quick and efficient production method has the potential to be scaled for useful hydrogen storage.
Solvent-free Mechanochemical Synthesis of Alane, AlH3: Effect of Pressure on the Reaction Pathway