A new synthetic procedure to make the condensed phase hydrogen storage material, ammonia borane (NH3BH3, abbreviated as AB), is described and compared with previous literature procedures. Ammonia borane with a gravimetric density ca. 194 gm H2 kg-1 and a volumetric density ca. 146 H2 litre-1, is a promising chemical hydrogen storage material for fuel cell powered applications. The work shows that ammonium borohydride, NH4BH4, formed in situ by the metathesis of NH4X and MBH4 salts (M = Na, Li; X = Cl, F) in liquid NH3, can be induced to decompose in an organic ether to yield AB in near quantitative yield. The purity of the AB prepared by this one-pot synthetic strategy is sufficient to meet the thermal stability requirements for on-board hydrogen storage.
ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering