Novel Hydrogen Storage

Title of the accomplishment:  Computational Materials Science for Energy:  Discovering Novel Hydrogen Storage Reactions

Authors and affiliations:  Chris Wolverton (Northwestern), Vidvuds Ozolins (UCLA)

A short description of the accomplishment: 

Hydrogen-fueled vehicles are reliant on a means to store hydrogen at a high density (by both volume and weight), as well as a means to extract fuel and refuel the system easily.  Currently available technologies based on compressed or liquid hydrogen are not sufficient.  Hence, many researchers are exploring the possibility to use solid-state hydride materials as a means to storage hydrogen at high densities.  Unfortunately, currently available materials typically either are much too heavy for practical use, or else bind hydrogen within the material much too strongly, thereby making it impractical to remove from the material.

We have recently developed a suite of computational materials science tools aimed at discovery of novel hydrogen storage materials. These computational tools are based on “first-principles” methods which start with a quantum-mechanical description of the interaction of electrons in a solid, and are truly predictive in the sense that properties of materials can be simulated, even if the materials have never been synthesized.  We have developed novel tools that allow the prediction of the thermodynamic conditions under which hydrogen can be inserted and removed from a given material, and allow the prediction of new atomic-scale crystal structure of predicted material. These capabilities have led to the prediction of several novel high-density hydrogen storage materials and reactions.

Explanation of the significance of this accomplishment (in layman's terms): 

Hydrogen is an extremely attractive alternative fuel for automobiles due to the potential for improved fuel efficiency, reduced or zero emissions, environmental benefits, and opportunities for domestic and renewable energy sources.  Vehicles utilizing hydrogen as a fuel are reliant on an efficient means of storing hydrogen on board the vehicle.  Currently available technologies fall far short of DOE targeted storage densities, both by volume and by weight. Thus, there is currently a global effort aimed at developing a material which will store hydrogen at a high gravimetric and volumetric density, and which will allow rapid, energy efficient (de)hydriding reactions at near-ambient conditions.A purely Edisonian experimental approach to discovery of novel storage materials via synthesis and characterization is time-consuming and inefficient due to the numerous possible reaction pathways, (often) slow reaction kinetics, as well as the sheer number of possible novel compositions. One approach to improve on this purely empirical search would be an accurate, predictive, physics-based modeling approach. Our highlight describes such an approach to create a “virtual laboratory” where new materials may be constructed and tested, all on computers, before they are ever synthesized in a laboratory. This type of computational screening can accelerate the discovery of novel crystal structures, reaction pathways, and material compositions for optimized storage performance.

The impact of the accomplishment:    The work described here has broad implications not merely to hydrogen storage, but to a wider variety of energy-related problems where new materials are needed:  battery electrodes, solar energy photovoltaics, thermoelectrics, fuel cells, etc.  In all of these areas, new materials are required to enable these alternative energy technologies, and in each case, computation can help guide experimental efforts and accelerate the pace of discovery.

Funding and computing program(s) that supported this work:

DOE Funding:  DE-FG02-07ER46433
NSF Funding:   CBET-0730929
Computing Program:  INCITE

Publications to cite when referencing this accomplishment:

V. Ozolins, E. H. Majzoub, and C. Wolverton, Phys. Rev. Lett. 100, 135501 (2008).

C. Wolverton, D. J. Siegel, A. R. Akbarzadeh and V. Ozolins, J. Phys.: Condens. Matter  064228 (2008);

J. Yang, A. Sudik, D. Siegel, D. Halliday, A. Drews, R. O. Carter III, C. Wolverton, G. J. Lewis, J. W. A. Sachtler, J.

J. Low, S. A. Faheem, D. A. Lesch, and V. Ozoliņš, “A Self-Catalyzing Hydrogen Storage Material,” Angewandte Chemie International Edition 47, 882-887 (2008).

A. Akbarzadeh, V. Ozoliņš, and C. Wolverton, “First-principles Determination of Multicomponent Hydride Phase Diagrams: Application to the Li-Mg-N-H System,” Advanced Materials 19, 3233-3239 (2007).

C. Wolverton and V. Ozolins, “Hydrogen storage in calcium alanate: First-principles thermodynamics and crystal structures,” Phys. Rev. B 75, Art. No. 064101 (2007).

D. Siegel, C. Wolverton, and V. Ozolins, “New Hydrogen Storage Reactions Based on Destabilized LiBH₄,” Physical Review B 76, Art. No. 134102 (2007).