Compressed hydrogen production via reaction between liquid ammonia and alkali metal hydride

Ammonia NH3 is recognized as one of the attractive hydrogen H2 carriers because it has a high hydrogen content of 18 mass% and it is easily liquefied under about 1 MPa of pressure at a room temperature. NH3 can react with alkali metal hydrides and generate H2 even at room temperature, resulting that metal amides are formed as reaction products. The H2 generation is exothermic reaction, and it is not effectively prevented by H2 partial pressure in a closed system as thermodynamic properties. In this work, we demonstrated the production of compressed H2 by the reaction between liquid NH3 and lithium hydride LiH in a closed pressure vessel, where liquid NH3 would realize better kinetic properties for the reaction with metal hydride than gaseous NH3. Actually, more than 12 MPa H2 was obtained within several hours.