Materials Designing of Li-based Complex Hydrides for Hydrogen Storage

摘要

Fundamental researches on complex hydrides are recently of great importance to developpractical hydrogen storage materials with higher gravimetric hydrogen densities than those ofconventional materials. First, in this paper, we clarify the correlation between B-H atomisticvibrations in [BH4]－-anion and melting temperatures of MBH4 (M = Li, Na, and K) asindexes of hydrogen desorption temperatures. This investigation implies that partial cationsubstitutions using smaller sized- and/or higher valenced-cations with higherelectronegativities might provide higher energy modes of Raman spectra, and then, lowerhydrogen desorption temperatures. Next, as an example, LiNH2 and its partial cationsubstitution materials are examined. At the start of the reaction, the hydrogen desorptiontemperature for LiNH2 with partial cation substitution drastically decreased, with the increasein Mg concentration, to around 370K for the sample with'= 30.