Eutectic Phenomenon of LiNH₂-KH Composite in MH-NH₃ Hydrogen Storage System.

Hydrogenation of a lithium-potassium (double-cation) amide (LiK(NH₂)₂), which is generated as a product by ammonolysis of litium hydride and potassium hydride (LiH-KH) composite, is investigated in details. As a result, lithium amide (LiNH₂) and KH are generated after hydrogenation at 160 °C as an intermediate. It is noteworthy that the mixture of LiH and KNH₂ has a much lower melting point than that of the individual melting points of LiNH₂ and KH, which is recognized as a eutectic phenomenon. The hydrogenation temperature of LiNH₂ in the mixture is found to be significantly lower than that of LiNH₂ itself. This improvement of reactivity must be due to kinetic modification, induced by the enhanced atomic mobility due to the eutectic interaction.