First-Principles Modeling of Hydrogen Storage in Metal Hydride Systems

Abstract

Executive SummaryThe objective of this project is to complement experimental efforts of MHoCE partners by using state-of-the-art theory and modeling to study the structure, thermodynamics, and kinetics of hydrogen storage materials. Specific goals include prediction of the heats of formation and other thermodynamic properties of alloys from first principles methods, identification of new alloys that can be tested experimentally, calculation of surface and energetic properties of nanoparticles, and calculation of kinetics involved with hydrogenation and dehydrogenation processes. Discovery of new metal hydrides with enhanced properties compared with existing materials is a critical need for the Metal Hydride Center of Excellence. New materials discovery can be aided by the use of first principles (ab initio) computational modeling in two ways: (1) The properties, including mechanisms, of existing materials can be better elucidated through a combined modeling/experimental approach. (2) The thermodynamic properties of novel materials that have not been made can, in many cases, be quickly screened with ab initio methods. We have used state-of-the-art computational techniques to explore millions of possible reaction conditions consisting of different element spaces, compositions, and temperatures. We have identified potentially promising single-and multi-step reactions that can be explored experimentally. IntroductionComplex metal hydrides have been extensively studied as candidate materials for hydrogen storage in vehicular and other applications.

Unstable Metal Hydrides for Possible on-Board Hydrogen Storage

“…The difference is that the Sc doped alloys suffer from much steeper plateaus than the Zr containing alloys. The partial substitution of the Cr by Mn alters the properties of both the parent alloys and their corresponding hydrides [43][44][45] in the following ways. The la ice contraction induced by Mn addition in TiCrMn makes the accommodation of a single H atom more difficult, and consequently this alloy exhibits a high desorption plateau pressure exceeding 10 MPa at 313 K [46].…”