(657e) Extending First-Principles Calculations of Complex Metal Hydrides to Predict Impurity Gases During Hydrogen Evolution

Complex metal hydrides have a potential as candidates for reversible hydrogen storage. First-principles calculations have played a useful role in examining large numbers of potential reaction mixtures to find materials with high H2 capacity and favorable thermodynamics. A significant disadvantage of most calculations of this type is that they have assumed that the only gaseous phase present is H2. We have developed a first-principles methodology for predicting not only the reaction thermodynamics of hydrogen evolution, but also the formation of other gaseous species that may act as impurities, including ammonia, methane, and borazine. Results from the application of this method to a range of ?destabilized? metal hydride mixtures will be presented. Calculations of this type will play an important role in future screening of metal hydrides for hydrogen storage applications.