Complex Hydrides—A New Frontier for Future Energy Applications

Personnel

Project Leader(s):
Vitalij Pecharsky

Principal Investigators:
Scott Chumbley, Duane Johnson, Marek Pruski

Overview

Hydrogen storage is one of the enabling technologies required to guarantee a successful future transition from fossil to hydrogen based fuels. The proposed multidisciplinary research effort draws on considerable experimental and modeling experience and expertise existing at the Ames Laboratory in order to achieve a fundamental understanding of the relationships between the chemical composition, bonding, structure, microstructure, properties and performance of novel hydrogen-rich solid systems. We seek solids that mimic the structure of methane and ammonia, where four or three hydrogen atoms encapsulate a single carbon or nitrogen atom forming neutral CH4 and NH3 molecules as opposed to conventional metal hydrides where a single hydrogen atom is encapsulated by several metal atoms.  Mechanochemistry and thermochemistry coupled with advanced characterization, theory, modeling, and simulations are used to understand composition-structure-processing-property relationships in complex materials systems consisting of light-metal hydride compounds and their derivatives.

The specific objectives are to address issues that will advance basic science of complex hydrides and open up possibili¬ties for their future use by drawing on the experience and expertise of principal investigators in materials science, physics and chemistry of com¬plex hydrides, X-ray diffraction (XRD), high-resolution solid-state nuclear magnetic resonance (NMR), electron microscopy, and first-principles theory and modeling.  Our goals are:

• Examine both mechanical energy- and thermal energy-driven phase transformations in chosen model hydride systems at and away from thermodynamic equilibrium.
• Establish the nature of the products and intermediates using state-of-the-art characterization methods.
• Identify events critical to achiev¬ing reversibility of hydrogen at mild conditions in model systems.
• Integrate experiment with first-principles theory to provide a fundamental under¬standing of the nature of hydrogen bonding and formation, structure, and stability of the model systems, the effects of mechanical energy, temperature, and pressure in controlling the na¬ture of hydrogen-metal bonds.
• Refine and extend the current understanding of the mechanisms of solid-state transforma¬tions from a few known hydrides to complex hydride-hydrogen systems by examining how chemical and structural modifications affect dehydrogenation/hydrogenation behaviors of selected model systems.
• Create a knowledge base relating composition, structure and properties of model hydrides by investigating the effects of varying stoichiometry and processing history on their crystal and microscopic structures, chemical, thermodynamic and physical properties.
• Develop predictive tools suitable to guide the discovery of materials at the atomic scale and tuning proc¬essing strategies to control the nano-, meso- and microscopic structures.

Highlights

Publications