Destabilization of LiBH4 by mixing with LiNH2

It was revealed that LiBH₄ is destabilized by mixing with LiNH₂ and the mixture desorbs a large amount of hydrogen. First-principles calculations predicted that the enthalpies of dehydrogenation for LiBH₄ alone and the mixture of LiBH₄+2LiNH₂ are 75 kJ/molH₂ and 23 kJ/molH₂, respectively. Motivated by this prediction, we experimentally examined the dehydrogenation properties for LiBH₄ and the mixture under hydrogen pressure. The amounts of desorbed hydrogen from LiBH₄ and the mixture at 703 K and 522 K were 10.6 mass% and 7.8 mass%, respectively. The dehydrogenation pressure of the mixture was much higher than that of LiBH₄ alone, although the mixture was measured at approximately 180 K lower temperature. This result suggests that the mixture is much unstable as compared with LiBH₄ alone.PACS 81.05.Zx; 71.20.Ps; 82.30.-b